ISSN 0038-3872
SOUTHERN CALIFORNIA ACADEMY OF SCIENCES
ULLETIN
Volume 115
Number 3
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115(3) 141-200 (2016,
December 2016
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Bull Southern California Acad. Set.
115(3), 2016, pp. 141-145
© Southern California Academy of Sciences, 2016
Site Fidelity of a Coastal Cactus Wren
{Camphylorynchus hrunneicapillus) on the Palos Verdes Peninsula
Ann Dalkey
Palos Verdes Peninsula Land Conservancy, 916 Silver Spur Road, Suite 206, Rolling Hills
Estates, CA 90274, USA, abdalkey@verizon.net
The coastal cactus wren (Camphylorhnehus hrunneicapillus) is a charismatic, though seden-
tary bird that inhabits thickets of prickly pear {Opuntia littoralis and O. oricola) and coastal
cholla (Cylindropuntia proUfera) in the coastal sage scrub and chaparral habitats of southern
California and Baja California, Mexico^ (Rea and Weaver 1990). Urbanization that took place
during the past century, with its attendant habitat loss, has deleteriously impacted this species.
On the Palos Verdes Peninsula, coastal cactus wrens occupy cactus habitat contained within
the five-hectare Palos Verdes Nature Preserve (Preserve) and undeveloped tracts interspersed
between the Preserve and urban development. As such, it is an isolated population that faces
threats through loss of genetic diversity.
Recently, two independent investigations have converged to demonstrate a remarkable in-
stance of site fidelity by a single individual. During 2012 and 2013, biologists from the U. S.
Geological Survey sampled 620 coastal cactus wrens in Ventura, Los Angeles, San Bernardino,
Riverside, Orange, and San Diego Counties to assess the impacts of habitat fragmentation using
contemporary genetic analysis (Barr et al. 2015). Birds that were captured for the genetic analy-
sis were banded to prevent re-sampling individuals^ A total of eight individuals were captured
and banded in the Preserve during the second year of this study. Each individual's location and
band number was recorded at capture and blood was drawn for the genetic analysis.
In 2014, the Palos Verdes Peninsula Land Conservancy (Conservancy) initiated a Citizen
Science Cactus Wren program to utilize volunteers to observe the coastal cactus wrens within
the Preserve. The Conservancy manages and restores habitat within the Preserve for several
special status species, as well as the coastal cactus wren. The program was designed to return
information about how the wrens utilized their habitat, within both existing habitat and newly
established areas of habitat. This is important information for the Conservancy in its mission to
restore cactus stands within the Preserve’s coastal sage scrub habitat.
The volunteers conducted weekly surveys within the Preserve’s Alta Vicente Reserve from
March through July during the breeding seasons in 2014 and 2015. The surveys were conducted
for 20 minute periods at specifically delineated territorial polygons within areas referred to
as West and East (Fig. 1). Observations were recorded by the minute and included number
of cactus wrens (adult, juvenile, or unknown), presence of predators, and several qualitative
behavior patterns from which frequencies could be computed (Table 1 ). For these surveys, the
enthusiastic volunteers took to the field outfitted with binoculars, spotting scopes, and cameras
equipped with telephoto lenses.
That coastal cactus wrens spend most of their time moving within the cactus thickets, rising
above the cactus for only brief moments, is reflected by the data collected by the Citizen Science
' Barr, K. R., A. G. Vandergast, and B. E. Kus. 2013. Genetic structure in the cactus wren in coastal south-
ern California. US. Geological Survey, Reston, VA, 27 pp. Available from: https://nrm,dfg.ca.gov/FileHandler.
ashx?DocumentID=65007 via the Internet. Accessed 20 February, 2016.
142
SOUTHERN CALIFORNIA ACADEMY OF SCIENCES
Fig. 1 . Alta Vicente West and East are shown in yellow in the upper left-hand box. The territorial polygons
are shown in the large map. The farmed cactus is visible as even rows adjacent to polygon AV04a.
Table 1. Ail observations from the 2015 Citizen Science Cactus Wren Program from 230 twenty-minute
surveys at 21 territories at Alta Vicente Reserve from 21 Feb 2015 through 25 Jul 2015. Each territory was
observed for 20 minutes and observations recorded by the minute. Occasionally multiple observations occurred
within a 1 -minute observation interval.
2015
Type of observation
Count
Percent
No observation
4101
88.98
Audio observation
65
1.41
Visual observation
213
4.62
Predator observed
32
0.69
Flight out to a different territory
77
1.67
Flight in from a different territory
73
1.58
Defensive/aggressive activity
2
0.04
Copulation
0
0.00
Nesting material in beak
15
0.33
Flight into nest
16
0.35
Flight out of nest
13
0.28
Feeding young in nest
1
0.02
Feeding young out of nest
1
0.02
Total observation intervals
4600
—
SITE FIDELITY OF A COASTAL CACTUS WREN
143
Fig. 2. Adult male photographed on 6 Jun 2015 that was banded two years earlier on 12 Jun 2013 as an
unknown sex. Image courtesy of Mai Lee.
volunteers in 2015. Aural and visual cactus wren observations occurred at a combined frequency
of 6.0% (Table 1). Birds were observed flying into or out of their territories during 2.3% of the
observations, whereas activities related to rearing their brood were observed during 1 .0% of the
observations.
Variations in the throat and breast patterns were used by Citizen Science volunteers to track
individuals. In 2014, after witnessing a pair copulate in the West, their distinctive color patterns
enabled the volunteers to determine the birds’ respective sex. Subsequently, the volunteers
tracked the behavior of the pair through their courtship, nesting, and the successful rearing of
two chicks. Throughout the nesting season, vocalization and defensive behaviors were primarily
the domain of the male while the female tended to the nest and chicks. After fledging, one chick
was witnessed mimicking its father’s boisterous defensive calls, leading to the conclusion that
the young individual was also male.
During the 2015 survey, one of the volunteers captured photos of a wren in the East at polygon
AV03c. When processing the photos later that day at home, she noticed that the bird was banded
with a single, silver band on its left, lower leg (Fig. 2). Similarly, I photographed the same
individual four weeks later on July 4, 2015 in polygon AV03f, and only noticed the band in
the photographs, for it was not visible with the naked eye or with binoculars. Each band has a
unique number, but unfortunately, the number on the band could not be discerned in any of the
photographs.
Earlier in 2013, two cactus wrens captured in polygon AV03c were banded with silver bands
on their lower left leg, one a female and the other unknown (Table 2). Due to the obscured band
144
SOUTHERN CALIFORNIA ACADEMY OF SCIENCES
Table 2. List of cactus wrens captured that were banded at the Alta Vicente Reserve following blood drawn
for genetic analysis during the 2012-2013 USGS field effort (from B. Kus (USGS personal communication). All
coordinates are in WGS84,
Site
Date banded
Age/Sex
Latitude
Longitude
Band ID*
AVlc
30-Jul42
Hatch year/Unk
33.74402
-118.40582
DGDG/YEYE : WHWH/Mre
AV2c
30-JuL12
Hatch year/Unk
33.74411
-118.40117
DGDG/YEYE : YEYE/Mre
AV03c
12-JUI1-13
Adult/Unk
33.74257
-118.40328
-/Msi : -/-
AV04a
12-Jun-13
Adult/Fernale
33.74401
-118.40144
-/Msi : ”/■
AV04a
12-Jun-13
Adult/Male
33.74401
-118.40144
-/- : /-Msi
* Top Left Leg/Bottom Left Leg : Top Right Leg/Bottom Right Leg.
Metal bands: Mre = federal red anodized aluminum band, Msi = federal silver aluminum band. Darvic bands:
DGDG =3 dark green, WHWH white, YEYE = yellow.
number in the individual photographed during the Citizen Science surveys, we could not directly
determine which bird from the 2013 banding effort was being observed. However, the banded
individual’s behavior indicated that it was a male. The bird was very noisy, acting defensively in
the presence of Citizen Science observers. It moved away from its youngsters that were foraging
nearby, circling around to perch on a tree tobacco {Nicotiana glauca), and vocalize defensively.
This was behavior very similar to that displayed by the male observed in 2014 by the Citizen
Science observers. Based upon the similar behavior, it was concluded that this bird in the East,
originally marked as an unknown at the time of banding, was certainly a male. Scarlett Howell
(USGS, personal communication) concurred that this behavior is characteristic of males and
that the banded bird was likely the individual identified by them as unknown in Table 2.
The banded bird observed during the 2015 survey was seen at locations throughout the east,
including the same polygon where it was banded and later photographed (AV03c). In May, this
male was observed foraging for its nestlings, flying out of polygon AV04a into farmed cactus
and back to the nest. Later in June, both adults were observed leading their chicks out of their
natal area (AV04a) and into a farmed patch of cactus {Opuntia ficus4ndica). Through June and
July, the family was frequently observed in the vicinity of the very polygon in which the male
was captured for banding.
Two years after banding, this male was operating in the very same area that it was originally
captured, exhibiting a remarkable degree of fidelity to the site. Although cactus wrens are known
to be a sedentary species, rarely flying more than one km in distance (Rea and Weaver 1 990),
this observation provides supporting evidence that this species is indeed, a sedentary bird.
Acknowledgements
This observation was the result of the effort of many. I thank the Palos Verdes Peninsula Land
Conservancy’s encouragement of research within the preserves that it manages and foresight for
creating the Citizen Science program. Much admiration is extended to the USGS biologists who
spent two years capturing the birds for sampling and banding while getting closer to cactus than
anyone would prefer. Additionally, they provided critical support in preparing this manuscript.
Finally, much appreciation is extended to the Citizen Science volunteers who brought their
dedication and passions to the field:
2014 Team: Helen Ashfor4 Bonnie Cohn, Bill Cullen, Joyce Daniels, Rina Gardner, Donna
McLaughlin, Evi Meyer, Linda Wedemeyer, and Lowell Wedemeyer.
SITE FIDELITY OF A COASTAL CACTUS WREN
145
2015 Team: Phil Camehl, Bonnie Cohn, Vanessa Craz, Joyce Daniels, Joan Krause, Donna
McLaughlin, Harry McWatters, Mai Lee, Evi Meyer, Nancy Fitzhugh, Marty Lewis, Alex
Retana, Lauren Singleton, and Pete Verenkof.
Literature Cited
Kelly R. Barr, B.E, Kus, K.L. Preston, S. Howell, E, Perkins, and A.G. Vandergast. 2015. Habitat fragmenta-
tion in coastal southern California disrapts genetic connectivity in the cactus wren (Campyiorhynchus
brunmicapillus). Mol. EcoL 24:2349-2363.
Rea, A.M. and K.L Weaver. 1990. The taxonomy, distribution, and status of coastal California cactus wrens.
Western Birds 21(3). 126 pp.
Bull. Southern California Acad. Sci.
115(3), 2016, pp. 146-155
© Southern California Academy of Sciences, 2016
Rodent Remo¥al of Fallen Joshua Tree {Yucca bremfoUa) Fruite
Mark Borchert
San Bernardino National Forest, RO. Box 292, Fawnskin, California 92333,
borchert 1 @charter net
Abstract — Joshua trees {Yucca brevifolia) produce large, iedehiscent fruits that contain
numerous large seeds. Seed dispersal in this species depends on rodents to dismantle
fruits and extract the seeds which they disperse tens of meters from the source. Using
camera trapping and fruits tied to bobbins, I show that white-tailed antelope squirrels
(Ammospermophilus leucurus) and kangaroo rats {Dipodomys spp.) moved intact, fallen
fruits 6 to 7 m from trees before opening them. Pocket mice (Chaetodipus fallax and
Perognathus longimembris) and pinyon mice (Peromyscus trueii) dismantled fruits and
harvested loose seeds but did not appear to move them although they readily harvested
loose seeds. Mobilizing fruits may be an important, overlooked step in the seed dispersal
process, especially if the fruits are indehiscent. Fruit-carrying behavior of rodents described
in this study adds to the dispersal distance of Joshua tree seeds.
Joshua tree is an iconic, widespread arborescent succulent of the Mojave Desert, In the
late Pleistocene Joshua trees were distributed over southeastern California, southern Nevada,
southeastern Arizona, and into much of northern Mexico (Cole et al. 2011). As temperatures
warmed during the Holocene, its distribution receded from Mexico, southestern Arizona and
southern California into a considerably smaller patchwork of disjuct areas (Cole et al. 2011;
Barrows and Murphy-Mariscal 2012). As climate continues to warm into the Century,
modeling suggests that Joshua tree likely will disappear in the southern part of its distribution
and perhaps expand north into Nevada (Cole et al. 2011).
The ability of Joshua tree to expand its range in response to the anticipated rapid warming
may be limited by seed dispersal that would effectively move it to suitable, unoccupied habitats
(Lenz 2001; Cole et al. 2011). Lenz (2001) hypothesized that beginning in the middle Miocene
(15.1-1 1.2 mya) mammals such as gomphotheres, mastadons and mammoths likely were long
distance dispersers of Joshua tree seeds. Indeed, he suggested its large, multi-seeded fruit may
have evolved in response to consumption by these large mammals. However, following the
extinction of megaherbivores in the late Pleistocene, Joshua tree seed dispersal now depends
entirely on the more limited dispersal (< 100 m) of rodents in the Sciuridae, Heteromyidae
and Cricetidae (Vander Wall et al. 2006; Waitman et al. 2012). Whether extinct megaherbivores
dispersed Joshua tree seeds is open to question (Waitman et al. 2012) but it is clear that the
role of rodent seed dispersal in relationship to present-day climate warming deserves careful
examination.
Joshua trees produce seeds in large, non-fleshy, indehiscent fruits. Seed release and dispersal
depends exclusively on rodents breaking into fruits and extracting seeds (Vander Wall et al.
2006; Waitman et al. 2012), although Vander Wall et al. (2006) also noted that rodents dragged
some fruits away from the source plant before opening them. Preliminary camera trapping of
fallen fruits in 2013 revealed that both white-tailed antelope squirrels and kangaroo rats moved
unopened fruits from beneath trees, but it was unclear how many fruits were taken, or how far
they moved them. If rodents carry fruits from the source, it would increase the total distance
146
RODENT REMOVAL OF FALLEN JOSHUA TREE
147
rodents disperse Joshua tree seeds. The goals of this study were: (1) to determine which rodent
species moved fruits from beneath trees and (2) to quantify the distances fruits were carried by
rodents in two contrasting Joshua tree habitats.
Materials and Methods
Study Area
The study was conducted in two 7.61 -ha areas located approximately 6 km north northeast
of Big Bear City, California. Both areas occupy gently sloping (average < 5°) topography in
the high desert of the San Bernardino Mountains at an elevation of 1 800 m. The Cactus Flats
(CF) site (34° 1973"N, 1 16°48^85'^W) has no documented occurrence of fire since 1910 when
records first began (fire history maps, Supervisor’s Office, San Bernardino National Forest),
although a wildfire burned to the southwest edge of the study area in 1946. The Lone Valley site
(LV) (34°17'84''N, 1 16°47'49"W) is located 3.5 km SSE of CF. There are no documented fires
for this area since record keeping began (1910).
The study area has a cold desert climate which is characterized by cold, snowy winters and
warm, dry summers. Average annual precipitation (1985 - 2014) based on a spatial interpo-
lation of regional climate stations (PRISM Climate Group, Oregon State University, Website
http://prism.oregonstate.edu created 6 July 2015) is 313 ± 145 mm SD, most of which falls
as snow from November to April. The study area also experiences occasional ephemeral sum-
mer and fall rainfall events. Both years of the study occurred during a prolonged drought with
136 mm of precipitation recorded in 2013 (43% of the average) and 255 mm (81% of the
average) in 2014.
Vegetation Sampling
At 26 points randomly located at each site, I recorded the vegetation cover and composition
using 10=m line transects. From each point I oriented a 10-m tape in a random direction. Every
0.5 m on the transect tape I recorded the following variables that intercepted a point: rock, bare
ground herbs and forbs, litter, coarse woody debris, live or dead shrubs, and live or dead trees.
The number of intercepts of each variable on the transect was divided by 20 to calculate percent
cover for each transect.
Camera Trapping
I camera-trapped the study areas to identify the species that removed fallen Joshua tree fruits.
In each study area, I located 10 camera-trapping stations in a 2 x 5 grid with spacing of
> 90 m between stations. At CF, fruits and seeds were photographed beginning 1 9 September
2013 and in 2014 beginning 15 July. At LV fruits and seeds were photographed beginning 26
October 2013 and beginning 21 August 2014.
At each station, I attached a BirdCam 2.0 camera (EBSCO Industries, Calera, Alabama USA)
to the bole of a Joshua tree "^35 cm above the ground. Approximately 75 cm from the lens I
placed 5 Joshua tree fruits on the ground and programmed cameras to take a photograph every
1.05 minutes beginning at sunset ("^1845 hours) for an average of 681 photos in the 12-hrs of
dark. Cameras flashed automatically every 1.05 minutes during the night. At sunrise 0630),
I replaced missing or partially opened fruits with new ones so that cameras photographed 5
fruits at 1.05-min intervals for 12 hours during the day. For each 12-hour period I recorded the
proportion of fruits removed from the camera field or opened within the camera’s field of view.
I camera-trapped each station for 3 days (72 hours), but I only analyzed the first 12-hr day or
148
SOUTHERN CALIFORNIA ACADEMY OF SCIENCES
night period when animals removed fruits or seeds from the station. If animals failed to remove
fruits or seeds from stations in the 72”hour period, the station was recorded as “not visited”.
I carried out the same 72-hour protocol using Joshua tree seeds that I extracted from fruits
collected at CF in 2013. In two side-by-side circular plastic dishes (1 .5 cm x 9.0 cm), I placed
~39.2 grams of seeds (to simulate the average number of seeds in 5 fruits) uninfested by yucca
moth larvae (Tegeticuh synthetica) (Borchert and DeFalco 2016). Seeds were neither counted
nor weighed after deployment.
Once seeds or fruits were discovered, rodents usually removed them in a rapid series of visits.
Trapping showed the average interval between visits ( ± SD) was 7 ± 5.4 minutes (n = 19). A
species was designated the harvesterer if there was at least one photograph of the animal in the
series of visits, and the time between visits did not exceed 1 5 minutes. In other words, if there was
no photograph of the animal, or if the interval between consecutive visits exceeded 15 minutes,
the sequence of visits was not analyzed. The little pocket mouse {Perognathus longimembris)
could not be distinguished from the San Diego pocket mouse (Chaetodipus fallax) in the
photographs so they were combined and are referred to as “pocket mice”. Similarly, Merriam’s
kangaroo rat (Dipodomys merriami) and the Pacific kangaroo rat {D. agilis) were combined and
are referred to as “kangaroo rats”. Live trapping, however, showed that Merriam’s kangaroo rat
was by far the most abundant kangaroo rat species (Borchert and DeFalco 2016).
Fruit Spool-and-Line Method
In the proximal end of fruits 6.0-8. 0 cm in length, I drilled a 0.8-mm diameter hole to a depth
of 5 cm. In this opening I inserted a 0.8 g bobbin (Danfield, Lancashire UK). At each study
site, I established a grid of 52 points (4 x 13) with 35-m spacing between points. I placed a
fruit under a Joshua tree (> 1.5 m in height) nearest each point and tied the bobbin thread to
a slender bamboo stake pushed into the soil Some fruits were moved but not eaten. These I
revisited daily until they were eaten, or moved and then eaten. Only fruits moved > 1.0 m were
considered mobilized outside the Joshua tree canopy. After a fruit was moved, I measured the
distance and compass direction to the point where it was taken.
Between 29 July and 31 July 2014 at CF I censused the 52 spooLand-line fruits just before
0630 and again at 1 845 and recorded which fruits were moved at night and during the day. In
this way, I compared the distances fruits were moved by noctural and diurnal rodents.
Statistical Analysis
I used the Mann- Whitney U test to compare differences in cover between the two sites and
distances fruits were moved between sites in each of the two years. T-tests were used to compare
the average number of fruits taken per station at the two sites.
Results
Vegetation
Vegetation differed between the two sites. Both sites had a similar cover of Joshua trees, but
CF cover was dominated by live shrubs (Lycium andersonii, Purshia tridentata van gianduiosa)
and bare ground (Table 1). In contrast, pinyon pine {Pinus monophylia) cover at LV averaged
23.5% whereas pinyons were absent in the transects at CF. The understory of LV was dominated
by herb cover, collapsed dead shrubs and downed Joshua trees (Table 1). Due to the low cover
of live shrubs, the understory of LV was considerably more open than CF.
RODENT REMOVAL OF FALLEN JOSHUA TREE
149
Table 1 . Plant species covep herbaceous cover, bare ground cover, dead shrub cover and litter cover for Cactus
Flats and Lone Valley. Values are mean cover ± 1 SD. Cover comparisons were made using Mann- Whitney U
for 26 transects at each site.
Plant species
Cactus Flats
Lone Valley
Statistical significance
Yucca brevifoiia
8.1 (9.8)
11.1 (17.0)
P = 0.95
Pirns monophylla
0.0
23.5 (20.4)
P < 0.001
Lycium mdersonii
12.7(10.9)
0.0
P< 0.001
Purshia tridentata var. glmduiosa
10.0(13.0)
3.1 (6.2)
P = 0.053
Artemisia tridentata
2.7 (6.7)
1.9 (4.9)
P = 0.91
Fremontodendron californicum
4.2(12.7)
0.0
F-0.08
Herbaceous
0.8 (2.7)
18.1 (15.8)
P < 0.001
Litter
0.0
7.7(11.4)
P < 0.001
Dead shrubs
11.2(14.8)
18.5(11.2)
P < 0.02
Bare ground
45.0 (19.2)
26.1 (21.7)
P < 0.001
Camera Trapping
There were 80 photographs of animals at fruit stations and 407 photographs at seed stations.
White-tailed antelope squirrels comprised the highest percentage (6 1 3%) of photographs at fruit
stations followed by kangaroo rats (163%) (Table 2). Kangaroo rats dominated photographs at
seed stations (45.5%) followed by white-tailed antelope squirrels (16.5%). Western scrub jays
(Aphelacoma californica) visited seed stations at LV in both years (Table 2). Although jays were
active at CF, they were not photographed at seed stations in either year.
Fruit Removal and Fruit Movements
Of the total 208 fruits placed under trees (2 sites x 2 years x 52 trees per site), 147 (70.7%)
were moved and subsequently opened, 29 (13.9%) had cut threads and the fruit was missing, 20
(9.6%) fruits were missing but the bobbin remained, 5 (2.4%) remained unopened at stations, 4
(1.9%) were moved but not opened, and 3 (1.4%) were taken into woodrat nests.
Of the 147 fruits that were moved and opened, 1 01 (68.7%) were taken beyond the canopy (>
1 .0 m) (Fig. 1 ), Fruit transport distances did not differ significantly between the two sites in 20 1 3
(Z = -”1.03, p = 030) or in 2014 (Z = 1.64, p = 0.10) (Table 3) even though the understory
was more open at LV than at CF (Table 1). Of the 101 fruits moved > 1.0 m, 10 (9.9%) were
Table 2. Number of photographs by species for each site and each year.
Cactus Flats Lone Valley
2013 2014 2013 2014
Fruits
Seeds
Fruits
Seeds
Fruits
Seeds
Fruits
Seeds
Wtiite-tailed antelope squirrel
15
18
12
30
15
16
7
3
Kangaroo rats
3
81
7
90
3
14
0
0
Pocket mice
2
25
0
8
2
20
0
4
Pinyon mouse
3
3
4
1
3
18
1
54
Merriam’s chipmunk
0
0
2
0
0
0
0
0
California ground squirrel
0
0
1
1
0
0
0
0
Western scrub jay
0
0
0
0
0
2
0
19
150
SOUTHERN CALIFORNIA ACADEMY OF SCIENCES
Distance intervals in meters
Fig. 1 . The number of spool-and-line fruits dispersed by distance intervals at each site. Distances were pooled
for 2013 and 2014. CF is Cactus Flats and LV is Lone Valley.
taken beyond 1 5 m (Fig. 1 ): the maximum distance a fruit was moved was 46.9 m, and the mean
maximum distance was 21.2 m (n = 4).
At CF in 2014 the mean ( it SD) distance fruits were moved by white-tailed antelope squirrels
during the day (8.3 m it 7.8 m, n = 7) did not differ significantly (Z = 0.95, p = 0.36) from the
mean distance of those moved at night by kangaroo rats (4.5 m it 3.4, n = 11). The maximum
distance a fruit was carried in the day was 25 m while the maximum distance at night was
11.3 m.
White-Tailed Antelope Squirrels
White-tailed antelope squirrels removed the highest percentages of fruits in late morning
(0900-1200) and early afternoon (1200-1500) (Fig. 2). In 2013 at CF they moved 22% of the 50
fruits from 6 stations, and at LV 76% of fruits from 8 stations (Table 4). The average number of
fruits taken per station at LV was significantly higher (t = 2.59, df = 1 1, p < 0.001) than the
average number taken at CF in 2013 (Table 4). In 2014 at CF, white-tailed antelope squirrels
moved 42% of the 50 fruits from 5 stations, and 52% were moved from 6 stations at LV The
average number of fruits taken per station did not differ significantly (t = 0.03, df = 9, p = 0.97)
between the two sites (Table 4). In the two years, five fruits were dismantled by white-tailed
antelope squirrels at CF while just one was opened at LV
Table 3. Fruit dispersal distances (> 1.0 m) at CF and LV for 2013 and 2014. Values are means ± 1 SD
(sample sizes).
Site
Year
Distance (m)
Cactus Flats
2013
6.1 ± 4.82(32)
2014
4.8 ± 4.7(19)
Lone Valley
2013
7.6 ± 5.9 (34)
2014
6.8 ± 6.2(14)
151
RODENT REMOVAL OF FALLEN JOSHUA TREE
Time of day In 4-hr intervals
Fig. 2. Percent of the fruits removed at the two sites in four-hour intervals over 24 hours. Values are for the
two years combined. CF is Cactus Flats and LV is Lone Valley,
In the two years at both sites, white-tailed antelope squirrels visited a total of 8 seed stations,
far fewer than the 25 stations visited for fruits. In 2013 at CF squirrels left 25-75% of the seeds
in dishes, although they removed nearly all the seeds in 2014. At LV they collected all the seeds
in both years. Nocturnal rodents invariably collected the small number of seeds not taken by
white-tailed antelope squirrels during the day.
Kangaroo Rats
Kangaroo rats visited stations between 1 800 and 0600 hours and removed the highest per-
centage of fruits just before midnight (Fig. 2). At CF kangaroo rats removed 41% of the 50 fruits
from 5 stations in 2013, and 59% of the fruits from 8 stations in 2014 (Table 4). In contrast, they
only harvested fruits at LV in 2013 and were not photographed removing fruits or seeds at LV
in 2014.
Table 4. Fruit removal from camera-trapping stations by white-tailed antelope squirrels and kangaroo rats.
Fruits removed per station are means ± 1 SD with sample sizes in parentheses. The percentages in parentheses
are for 50 fruits (5 fruits x 10 stations). CF is Cactus Flats and LV is Lone Valley.
Site
Year
Stations visited # Fruits taken (%)
# Fruits removed per station
CF
2013
6
White-tailed antelope squirrels
11 (22%)
1.8 ± 0.9(6)
2014
5
21 (42%)
4.2 ± 1.6(5)
LV
2013
8
38 (76%)
4.4 ± 0.8 (8)
2014
6
26 (52%)
4.2 ± 1 .3 (6)
CF
2013
5
Kangaroo rats
17(34%)
3.2 ± 1.3(5)
2014
6
24 (48%)
4.4 ± 1 .3 (6)
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SOUTHERN CALIFORNIA ACADEMY OF SCIENCES
At CF kangaroo rats collected seeds at 5 stations in 2013 and at 8 stations in 2014. They
collected nearly all of the seeds after multiple visits. Pinyon mice, and sometimes pocket mice,
harvested the few seeds not taken by kangaroo rats. In 2013 at LV, kangaroo rats gathered seeds
from 2 stations; seeds not taken by kangaroo rats were collected by pinyon mice at LV.
Pocket Mice and Pinyon Mice
Pocket mice dismantled 7 fruits at 2 stations at LV in 2014, and three fruits were removed.
Pinyon mice opened 7 fruits at 2 stations at CF and removed 3 fruits. They collected seeds from
5 stations at LV and from 3 stations at CF in the two years. Like pocket mice, pinyon mice
harvested more seeds than fruits. In the two years, they took seeds from two stations at CF and
from 7 stations at LV
A pair of western scrub jays was present at each site in both years. At LV they visited 4 stations
in two years and removed all the seeds from two stations, one in 2013 and one in 2014 (Table 2).
At each site they carried one spooLand-line fruit a short distance (< 3 m). A California ground
squirrel (Otospermophiius beecheyi) briefly visited seed dishes at one CF station in 2014.
Discussion
White-tailed antelope squirrels moved fallen Joshua tree fruits at both sites in both years and
visited more fruits (63%) than seed stations (20%). Similarly, in southern Nevada, white-tailed
antelope squirrels visited just 13% of the 23 stations supplied with Joshua tree seeds (Waitman
et al. 2012). Although fruits collected at CF in 2013 were large (averaging 4.3 cm in diameter
and 6.6 cm in length) and weighed 14 g (dry), white-tailed antelope squirrels (100-1 10 g) easily
carried them from the stations. Moreover, because the average fruit contained 95 undamaged
seeds, they efficiently moved numerous seeds in a single visit, as opposed to the multiple
visits required to carry loose seeds (Table 2). Because shurb cover was low at LV compared to
CF, I expected fruits to be moved greater distances but there was no significant difference in
m.ean distance between the two sites. At CF, rodents carried fruits through dense shrubs stems
(especially Lycium) into openings and through additional shrub patches before opening them.
As a result, threads often traced highly circuitous routes. At LV rodents frequently hid fruits next
to downed Joshua tree stems near the location of deployment. Fruits carried greater distances
often were taken in straight lines.
In addition to collecting fallen fruits, white-tailed antelope squirrels are agile climbers (Zem-
bal and Gall 1980; Waitman et al. 2012, Borchert and DeFalco 2016). In both years at CF
squirrels removed or opened 24 - 28% of canopy fruits (Borchert and DeFalco 2016). For exam-
ple, in 2014 I placed a sample of spooLand-line fruits in eight trees. Camera trapping showed
white-tailed antelope squirrels climbed trees and dismantled fruits but they also carried the
spool-and-line fruits to the ground, where they dispersed them in the same way they dispersed
fallen fruits in this study (unpublished data).
The results of this and other studies suggest white-tailed antelope squirrels are likely keystone
seed dispersers in deserts of the arid West because it is a relatively large rodent, is an excellent
climber, possesses cheek pouches for seed storage, and scatterhoards seeds (Beck and Vander
Wall 2010). Furthermore, it is widely distributed across eight states (Belk and Smith 1991), and
is relatively abundant (Clark 2010; Borchert and DeFalco 2016). In southern Nevada, Bradley
(1968) found seeds of 11 shrubs and six forbs and grasses in the cheek pouches of white-
tailed antelope squirrels including T brevifolia, Z baccata and Y. schidigera. Squirrels also
collected and dispersed fallen Pinus monophylla seeds (Hollander and Vander Wall 2004) and
the fruits of Prunus andersonii (Beck and Vander Wall 2010). White-tailed antelope squirrels
RODENT REMOVAL OF FALLEN JOSHUA TREE
153
removed 75% of the fruits in the canopies of E andersonii as well as the seeds and fruits of
Y. brevifoiia (Zembal and Gall 1980; Waitmaii et al 2012; Borchert and DeFalco 2016). At
CF I camera-trapped squirrels removing both seeds and fruits of Fremontodendron californica
from beneath shrubs. In 2015 at LV, they were camera-trapped removing and opening fruits of
Opuntia phaeacantha (0.5-1 m in height). White-tailed antelope squirrels likely climb other
desert shrub and tree species to obtain fruits and seeds.
Although Merriam's kangaroo rats, the most common kangaroo rat species on the two sites
(Borchert and DeFalco 2016), are considerably smaller (40-50 g) than white-tailed antelope
squirrels, they also carried fruits, sometimes tens of meters. Kangaroo rats are well-known seed
dispersers (Longland 1994; Jenkins et al 1995; Jenkins and Breck 1998; Longland et ah 2001,
Waitman et al 2012; Longland and Ostoja 2013) but carrying large fruits has not been described
for this species. I photographed this species removing fruits at CF in both years but not at LV
where they gathered seeds in one (2013) of the two years. Still, the maximum length of camera
trapping a station was only 72-hours, so fruit mobilization by kangaroo rats also may have
occurred at LV but was not photographed. They readily collected loose seeds from dishes and
typically visited stations multiple tim,es (Table 2) until all but a few seeds remained.
Because nearly all kangaroo rat species do not climb, fruit removal by these species is likely
confined to years of high fruit production when they fall to the ground (Borchert and DeFalco
2016). Nevertheless, even in years of low fruit production, white-tailed antelope squirrels con-
sume or disperse canopy fruits before they reach the ground. Therefore, in low production years
non-climbing rodents only have access to seeds in unopened fruits on the ground abandoned
by white-tailed antelope squirrels or to seeds left in dismantled fruits. Pinyon mice and pocket
mice removed small numbers of fruits and were likely more important in dispersing seeds than
fruits.
Fruit removal by kangaroo rats and white-tailed antelope squirrels increases the known disper-
sal distance of Joshua tree seeds. The weighted average distance of primary dispersal by rodents
in southern Nevada was 13.7 m, and the weighted averaged distance of secondary dispersal was
12.1 m, summing to 25.8 m (Vander Wall et al. 2006). In this study the weighted average fruit
movement distance for the two sites was 6.4 m which, when added to 25.8 m for seed dispersal
sums to 32.2 m, an increase of almost 25%. In this study the mean maximum distance for fruits
was 21.2 m, which when summed with Vander Wall et al.’s (2006) estimate of maximum primary
seed dispersal of 30.0 m totals 5 1.2 m, or a 4 1 % increase over estimate when only seed dispersal
is considered. Nevertheless, 5 1 .2 m does not include the mean maximum distance for secondary
seed dispersal.
Fruit movement in this study demonstrates bow a thorough examination of disperser behavior
may reveal unobserved steps in the dispersal process, steps that increase seed dispersal distances.
For example, seed dispersal by agoutis {Dasyprocta sp.) illustrates how dispersal distances can
increase once its foraging behavior was folly examined. In central Amazonia agoutis cached
single Brazil nuts (BerthoUetia exceisa) within 1 0 m of the source (Tuck Haugaasen et al 2010).
However, a second study of Brazil nut dispersal (Tuck Haugaasen et al. 2012) showed agoutis
carried unopened fruits an average of 20.8 m before they scatterhoarded nuts another 4 m.
Fruit and seed dispersal together averaged 29.2 m. Thus, studies that rely only on marked seeds
may underestimate dispersal distances, especially for plant species with indehiscent fruits (Tuck
Haugaasen et al. 2012). In the Sonoran and Mojave deserts of California at least 22 plant species
are serotinous like Y. brevifoiia (Martinez-Berdeja and Ezcurra 2015) suggesting that other
species may benefit from the frait-carrying behavior of Ammospermophilus and Dipodomys.
If fruit mobilization is a widespread phenomenon in Joshua trees, seed dispersal distances
for this arborescent succulent may be greater if, in addition to fruit displacement, seeds are
154
SOUTHERN CALIFORNIA ACADEMY OF SCIENCES
re-cached multiple times. Repeated re-caching increases dispersal distances because the cumu-
lative distance from the source increases with each successive re-cache (Vander Wall and Joyner
1999, Roth and Vander Wall 2005, Perea et al. 2011, Jansen et al. 2012, Wang et al. 2014),
Jansen et ah (2010) followed the dispersal of a large-seeded palm {Astrocaryum standleyanum)
by Central American agoutis {Dasyprocta punctata). After caching and re-caching palm seeds
numerous times (up to 36), agoutis moved 33% of the seed > 100 m and some seeds up to 900
m. Vander Wall et al. (2006) recorded secondary caching of Joshua tree seeds, but tertiary or
quaternary caching could further increase seed dispersal distances.
Several researchers have suggested the limited seed dispersal of Joshua tree as a major
impediment to its migration in response to climate change (Cole et al. 2011; Barrows and
Murphy-Mariscal 2012). Nevertheless, it is important to note that the expansion of a species
outside its current range in response to climate change depends on factors besides seed dispersal
including: seed availability (Kroiss et al. 2015), abundance of germination microsites (Kroiss
et al 2015), interspecific plant competition (Urban et al. 2013; Tomiolo et al. 2015), interactions
with obligate pollinators (Blatrix et al. 2013), disturbance (Serra-Diaz et al 2015; Springer et al.
2015) and landscape heterogeneity (Chardon et al. 2015; Serra-Diaz et al. 2016).
California scrub jays are well-documented long distance dispersers of the acorns of California
oaks (Pesendorfer et al. 2016) and were present at both sites. In this study scrub jays dispersed
small numbers (< 3) of fruits short distances (< 2 m) although the thread may have discouraged
them from flying far. They also were photographed collecting loose seeds at LV Nevertheless,
even when fruits were abundant, I did not observe them opening fruits to extract seeds. The
role of scrub jays in the dispersal of Joshua trees remains unresolved. Even if they did not open
fruits, it is possible that they collect and disperse seeds from partially open fruits attached to the
panicle or dismantled fruits on the ground.
Acknowledgements
I wish to thank Lesley DeFalco and Stephen Vander Wall for commenting on the draft
manuscript. I thank the two anonymous reviewers of the manuscript for their helpful suggestions
and edits.
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Bull. Southern California Acad. Sci.
115(3), 2016, pp. 156-175
© Southern California Academy of Sciences, 2016
Status of the Endangered Chorro Creek Bog Thistle Cirsium fontinale
van obispoeme (Asteraceae) in Coastal Central California
Christopher P. Kofron* and Neil Havlik^
^ U.S. Fish and Wildlife Service, 2493 Portola Road, Suite B, Ventura, CA 93003,
chrisjiofron @fws.gov
^City of San Luis Obispo, San Luis Obispo, CA 93401, neilhavlik@aol.com
Abstract. — Chorro Creek bog thistle Cirsium fontinale van obispoense (Asteraceae) is a
biennial or short-lived perennial plant up to 2 m tall that occurs only in San Luis Obispo
County, west of the outer coast ranges. It was listed as endangered under the California
Endangered Species Act in 1993 and the U.S. Endangered Species Act in 1994. Chorro
Creek bog thistle is a serpentine endemic, occupying perennial seeps and springs in ser-
pentine soil and rock in western San Luis Obispo County from north of San Simeon Creek
to south of the city of San Luis Obispo. At federal listing in 1994 Chorro Creek bog thistle
was known from nine occurrences (one of these presumed extirpated) and with an estimate
of <3,000 individuals. In 2016 the conservation status of Chorro Creek bog thistle is sub-
stantially improved because of an increased number of known occurrences along with an
increased number of occurrences that are protected. Only two of nine known occurrences
were protected in 1994, whereas 10 of 21 occurrences are protected in 2016. There are
many other locations with habitat that have not been searched, in particular on private land.
It is highly likely that additional unknown occurrences exist in San Luis Obispo County,
and possibly also in Monterey County to the north and Santa Barbara County to the south.
In consideration of the available information, we conclude that Chorro Creek bog thistle is
still endangered. However, when using the international standards of lUCN, we assign the
category data deficient because of the limitations of our data.
The fountain thistle Cirsium fontinale is a plant in the aster and sunflower family (Asteraceae)
with a known geographic range extending from San Francisco County southward to San Luis
Obispo County in western California. Three varieties are recognized (Baldwin et al. 2012):
Crystal Springs fountain thistle C. fontinale van fontinale. Mount Hamilton fountain thistle
C fontinale van campylon, and Chorro Creek bog thistle C. fontinale van obispoense. Crystal
Springs fountain thistle occurs west of San Francisco Bay in San Mateo and San Francisco
Counties. Mount Hamilton fountain thistle occurs south and east of San Francisco Bay in
Alameda, Santa Clara and Stanislaus Counties. Chorro Creek bog thistle occurs only in San
Luis Obispo County, 176 km south of the nearest occurrence of Mount Hamilton fountain thistle
(USFWS 2014). Chorro Creek bog thistle and Crystal Springs fountain thistle were listed as
endangered under the U.S. Endangered Species Act in 1994 and 1995 (U.S. Fish and Wildlife
Service [USFWS] 1994, 1995), respectively, and also under the California Endangered Species
Act in 1993 and 1979 (California Department of Fish and Wildlife [CDFW] 201 6b), respectively.
Mount Hamilton fountain thistle is not listed.
Chorro Creek bog thistle is a biennial or short-lived perennial plant up to 2 m tall. Its spiny
leaves have glandular hairs on the upper and lower surfaces, and its flowers are white, pink or
lavender with a drooping posture. Each flower head produces ^73 seeds (mean), which are up
to 4 mm long (Turner and Herr 1996) and with a pappus (set of bristles) that aids dispersal.
156
STATUS OF THE ENDANGERED CHORRO CREEK BOG THISTLE
157
Chorro Creek bog thistle is diagnosed from the other two varieties by combination of several
morphological characteristics of the stem, leaf, inflorescence, flower and fruit, Baldwin et aL
(2012) provide complete descriptions of the three varieties.
At federal listing in 1 994, Chorro Creek bog thistle was known from nine occurrences, one
of these presumed extirpated, and with an estimate of <3,000 individuals. Identified threats
were cattle grazing (trampling, herbivory), proposed development, water diversions, road main-
tenance, inadequate legal protection, stochastic events (in particular drought), and invasive
(non-native) plants (USFWS 1994). Two occurrences were protected. USFWS (2014) reviewed
the conservation status of Chorro Creek bog thistle (19 known occurrences) and recommended
no change in the legal listing status. Our purpose is to review and enhance the knowledge of
Chorro Creek bog thistle, in particular its distribution, ecology, abundance, threats, management
and conservation status in 2016.
Materials and Methods
We surveyed and censused many occurrences of the Chorro Creek bog thistle in San Luis
Obispo County from 2009 to 2016, and we found five previously unknown occurrences. We
counted and estimated (after gaining experience by counting) the number of plants in each
colony (a spatial group of separate individuals) and occurrence that we observed. We considered
reports of the USFWS and CDFW, data in the California Natural Diversity Database (CDFW
2016a), and personal communications from other biologists who also observed the species.
Using all available information, we summarize the knowledge of Chorro Creek bog thistle in
2016. We consider a location with the species as a separate occurrence if it is >0.4 km from
the nearest occurrence (California Department of Fish and Game 2011). The stated distances
and the stated numbers of plants are approximates. Elevations were determined using tools in
Google Earth. Latin and comm^on names of plants follow Baldwin et al. (2012), with exception
of C fontinale var. obispoense for which we use Chorro Creek bog thistle rather than San Luis
Obispo fountain thistle. Areas (ha) of properties are from records of the County of San Luis
Obispo and the City of San Luis Obispo. We provide the relevant and available details for each
occurrence in Appendix 1 . The findings and conclusions in this article are those of the authors
and do not necessarily represent the views of the USFWS.
Results and Discussion
Chorro Creek bog thistle (Fig. 1) is a serpentine endemic (Safford et al. 2005; Baldwin et al.
2012.), occupying perennial seeps and springs in serpentine soil and rock in western San Luis
Obispo County (Fig. 2). Although we conducted no soil tests, each of the 2 1 known occurrences
is on or adjacent to a serpentine deposit according to geologic maps (Wiegers 2009, 2010)
and/or geologist David Chipping (USFWS 2014). Serpentine soil and rock are characterized
by low calcium to magnesium ratios, and with calcium at significantly lower levels relative to
surrounding areas. In addition, serpentine soil and rock frequently contain elevated levels of
heavy metals (e.g. iron, nickel, chromium, cobalt), which are toxic to most other plants, and
they are often deficient in essential plant nutrients (e.g. nitrogen, potassium, phosphorus; Brady
et al. 2005). Because of their ultramafic origin, which in western San Luis Obispo County is
associated with tectonics and subduction (Wiegers 2009, 2010), serpentine substrates are often
steep outcrops (Brady et al. 2005). Accordingly, we report that Chorro Creek bog thistle occur
mostly on slopes (Fig. 3).
Chorro Creek bog thistle typically live 2 or 3 years. The plant forms a rosette of leaves in
the first year that can attain up to 0.9 m diameter. Stalk development begins during February
158
SOUTHERN CALIFORNIA ACADEMY OF SCIENCES
Fig. 1 . Flower head of Chorro Creek bog thistle Cirsium fontinale var. obispoense on Camp San Luis Obispo
(occurrence 3), San Luis Obispo County, California (12 May 2005). Photo courtesy of David Magney, Ojai,
California.
or March of the second year, and it continues to May or early June with some plants attaining
>2 m height, although 0.5 to 1.0 m is most common. Flowering generally occurs during May to
mid” June, and with some branched stalks bearing >25 flowers. After flowering and setting seed,
the stems turn brown, lean to one side and eventually fall. Some living plants may persist into
a third year if sufficient energy reserves remain. Under drought conditions, stalk development
is less vigorous, and the buds and flower heads develop substantially faster, but fewer actually
flower. This is likely an adaptive strategy for quickly producing seeds before the substrate dries.
At several occurrences with dense, invasive grasses (e.g. Laguna Lake Natural Reserve), Chorro
Creek bog thistle are often unable to spread their leaves into rosettes. Instead, they appear like
spiny romaine lettuce, most of which flower and set seed. As the invasive grasses die back in
midsummer, the leaves of the plant fall outward and form a carpet around its center, which
suppresses future growth of grasses. This results in a substantial amount of seed germination
within the circle of old leaves during the following year and with little seed germination beyond
the circle (Chipping in USFWS 2014).
In 2016, we report that the 21 known occurrences of Chorro Creek bog thistle comprise
a geographic range of 253 km^, extending from north of San Simeon Creek (35.63087,
-121.06535) to south of the city of San Luis Obispo (35.239909, -120.699012; 58 km dis-
tance). The 12 occurrences (10-21) identified since listing have expanded the geographic range
by 69% (150 km^), and six of these occurrences are protected while six are not: protected —
four occurrences (14, 15, 16, 17) on public lands owned by the City of San Luis Obispo, one
STATUS OF THE ENDANGERED CHORRO CREEK BOG THISTLE
159
Fig. 2. The known geographic distribution of Chorro Creek bog thistle Cirsium fontinale var. obispoense
in western San Luis Obispo County, California. Black dots indicate the 21 known occurrences, and the arrow
indicates the two northernmost occurrences near San Simeon Creek. The plant inhabits perennial seeps and springs
in serpentine soil and rock (gray shaded areas). We recommend searching for additional occurrences in San Luis
Obispo County in the serpentine soil and rock indicated in this map. See also Fig, 4 and 5.
occurrence (13) on private property with a conservation easement to the City of San Luis Obispo,
and one occurrence (12) legally protected on private property with an open-space easement to
the County of San Luis Obispo; not protected one occurrence (19) on a property owned by
the California Army National Guard, four occurrences (10, 1 8, 20, 21) on five private properties,
and a “lost” occurrence (11; precise location unknown) likely on a private property. Also, it is
highly likely that additional unknown colonies and occurrences exist in San Luis Obispo County,
and possibly in Monterey County to the north and in Santa Barbara County to the south (Figures
2, 4 and 5), and in particular on private property.
All known occurrences of Chorro Creek bog thistle are west of the outer coast ranges, and
at 38 to 380 m elevation. Occurrences 1 and 18 (San Simeon Creek watershed; Table 1) are
the northernmost occurrences, and with a distance of 37 km from the nearest occurrence (9,
tributary^ of San Bernardo Creek in Chorro Creek watershed) to the southwest. The other 1 8
occurrences are clustered in three primary watersheds (Chorro Creek, San Luis Obispo Creek,
Los Osos Creek), with a maximum distance of 5.8 km between any two occurrences. Occurrence
2 at Laguna Lake Natural Reserve in the city of San Luis Obispo comprises multiple colonies
at 14 seeps. Occurrence 13 near Loma Bonita Drive is 1.6 km to the southeast on the same
serpentine outcrop in the city of San Luis Obispo. Occurrences 4, 5, 7, 8, 14, 15, 16 and 21
are associated with a serpentine outcrop in Irish Hills southwest of the city of San Luis Obispo,
and occurrence 1 2 near Serpentine Lane is also in Irish Hills on a separate serpentine outcrop
4.1 km west of these occurrences. Occurrences 10, 11 and 17 occupy a serpentine outcrop
160
SOUTHERN CALIFORNIA ACADEMY OF SCIENCES
Fig. 3. Occurrence 13 of Chorro Creek bog thistle Cirsium fontinale var. obispoense in the central part of
the city of San Luis Obispo (the urban area), San Luis Obispo County, California (16 December 2011). This
occurrence comprises a single colony at a seep on private property that is used for cattle grazing. Trampling is
not a threat because the plants are on a steep, rocky slope. The landowner granted a conservation easement to the
City of San Luis Obispo (the local government).
immediately north and east of the city of San Luis Obispo. Occurrences 3, 6, 9, 19 and 20
are associated with serpentine outcrops in foothills north and west of the city of San Luis
Obispo.
Most occurrences (1, 2, 3, 4, 6, 8, 9, 12, 14, 17, 18, 19, 20) of Chorro Creek bog thistle
are comprised of multiple colonies. Information on abundance is limited because recent census
data are lacking for 1 1 occurrences (Table 2). Although 1 0 occurrences were censused during
the past 5 y (2012 to 2016), four were last censused in 1993, one in 1987, one in 1997, one
in 2001, and one in 2007. Only occurrence 3 on Camp San Luis Obispo was subject to formal
and regular monitoring (1994 to 2008). Currently, 14 occurrences are subject to informal and
irregular monitoring, and seven occurrences have no monitoring. Six occurrences were reported
to comprise >1,000 plants at particular points in time: occurrence 1 (San Simeon Creek),
>1,000 plants in 1984 (CDFW 2016a); occurrence 2 (Laguna Lake Natural Reserve), most
recently 1,718 plants in 2016 (pers. obs.); occurrence 3 (Camp San Luis Obispo), most recently
1,782 plants in 2014 (Kevin Merk, San Luis Obispo, pers. comm. 2016); occurrence 6 (El
Chorro Biological Reserve), most recently 2,200 plants in 1993 (Chipping in USFWS 2014);
occurrence 10 (Miossi Creek), >1,000 plants in 1997 (CDFW 2016a); and occurrence 12 (near
Serpentine Lane), >4,000 plants in 2001 (CDFW 2016a). The greatest estimates for the 15 other
occurrences range from 3 to 800 plants.
STATUS OF THE ENDANGERED CHORRO CREEK BOG THISTLE
161
Fig. 4. Serpentine soil and rock (gray shaded areas) in Monterey County^ California. Chorro Creek bog thistle
Cirsium fontinale van obispoense inhabits perennial seeps and springs in serpentine soil and rock in western
San Luis Obispo County, as currently known. The arrow indicates the two northernmost occurrences near San
Simeon Creek. We recommend searching for additional occurrences in Monterey County in potential habitat in
the serpentine soil and rock indicated in this map. See also Fig. 2 and 5.
162
SOUTHERN CALIFORNIA ACADEMY OF SCIENCES
Fig. 5. Serpentine soil and rock (gray shaded areas) in Santa Barbara County, California. Chorro Creek bog
thistle Cirsiumfontinale var. obispoense inhabits perennial seeps and springs in serpentine soil and rock in western
San Luis Obispo County, as currently known. The group of black dots (upper left) indicates the southernmost
occurrences in the vicinity of the city of San Luis Obispo. We recommend searching for additional occurrences
in Santa Barbara County in potential habitat in the serpentine soil and rock indicated in this map. See also Fig. 2
and 4.
Since 1968 the Eurasian flower-head weevil Rhinocyllus conicus has been introduced at
multiple locations in North America (Herr 2004) as a biocontrol agent for invasive thistles
Carduus and Silybum, including San Luis Obispo County in 1973 (Goeden et al. 1985) and
in particular Camp San Luis Obispo in the early 1980’s (California Army National Guard in
USFWS 2014). The adult weevils congregate on young thistles in early spring to feed and
mate. They lay eggs (mean 192 eggs per female) on developing flower heads into which the
subsequent larvae tunnel and feed on. Pupation occurs in the flower head, with adults emerging
in midsummer. One generation per year is produced (Zwolfer and Harris 1984). By 2005 the
weevil occurred in 26 states and Canada (Dodge 2005), with multiple reports of feeding also
on native thistle Cirsium (Turner et al. 1987). This weevil was reported feeding on Chorro
Creek bog thistle at three occurrences: San Simeon Creek (Herr 2004; Chipping in USFWS
2014;), Laguna Lake Natural Reserve (Herr 2004), and Camp San Luis Obispo (California Army
National Guard in USFWS 2014). At San Simeon Creek, 28% of the flower heads were infested
throughout the growing season (42% in July 1995), and with 27% (mean) of seeds destroyed
in the infested flower heads. Seed loss was 8% of total seed set at the study site (Turner and
Herr 1996; Herr 2004; John Herr, US. Dept. Agric., Albany, Calif, pers. comm. 2012). Turner
and Herr ( 1 996) reported a phenological difference in peak egg laying of the weevil in relation
to flower head production of Chorro Creek bog thistle. At Laguna Lake Natural Reserve (Herr
2004), infestation rates were 32% in May (1996) and 5% in July (1995). Magney (USFWS 2014)
saw no weevils at Camp San Luis Obispo in September (2005), although the California Army
STATUS OF THE ENDANGERED CHORRO CREEK BOG THISTLE
163
Table 1 . Distribution of Chorro Creek bog thistle Cirsium fontinale var. obispoeme in western San Luis
Obispo County, California: the primary and secondary watersheds of the 2 1 known occurrences.
Primary watershed
Secondary watershed
Occurrence
San Simeon Creek
1
North Fork (some colonies)
H
Chorro Creek
3
19
Pennington Creek
6
San Bernardo Creek
9
San Luisito Creek
San Luis Obispo Creek
13
21
Prefiimo Creek
2 Laguna Lake
4
5
Froom Creek
7
8
14
15
16
Miossi Creek
10
Reservoir Canyon Creek
11
u
Los Osos Creek
12
National Guard (USFWS 2014) subsequently observed weevils feeding on Chorro Creek bog
thistle in 2012, Lutz (2013) saw no evidence of weevils at Reservoir Canyon Natural Reserve
(occurrence 11). In sum., we consider the Eurasian flower-head weevil a threat because it was
seasonally destroying a substantial number of seeds at the occurrence where studied.
Regarding cattle grazing in and near the habitat of Chorro Creek bog thistle, herbivory
and trampling are the two obvious issues. At Camp San Luis Obispo, cattle grazing caused a
substantial decrease in established plants and a substantial increase in juvenile plants (Mardesich
and Laughlin in USFW 2014). Along with Chipping (Calif. Polytech. St. Univ., pers. comm.
2012) and Nancy Siepel (Calif. Dept. Transport., San Luis Obispo, pers. com.m. 2012) who
observed cattle grazing in the vicinity of Chorro Creek bog thistle, we consider the effects of
herbivory as minor and not a threat because the spiny plants are generally unpalatable (USFWS
1998). However, trampling can severely damage established plants, especially when water is
limited and cattle congregate at the water. In addition, cattle can damage the structure of the
riparian area or seep (e.g., damage to streambank by hooves, damage to soil by defecation;
Swanson et al 2015).
The USFWS (2014) identified stochastic events as a threat to Chorro Creek bog thistle. Species
with small populations are vulnerable to extinction by stochastic events (Shaffer 1981, Ricklefs
2008). This means that environmental or demographic chance or randomness can cause the
population size to fluctuate, and in small populations the fluctuations are more likely to include
zero. The 21 occurrences of Chorro Creek bog thistle exist as a metapopulation in a relatively
small geographic area (271 km^), and with only six occurrences reported to contain >1,000
individuals. Therefore, we consider stochastic events an ongoing threat.
Table 2. Approximate numbers of Chorro Creek bog thistle Cirsium fontinale var. obispoense in the 21 known occurrences in western San Luis Obispo County, California.
164
SOUTHERN CALIFORNIA ACADEMY OF SCIENCES
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STATUS OF THE ENDANGERED CHORRO CREEK BOG THISTLE
165
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The USFWS (2014) identified climate change as a new threat to the Chorro Creek bog thistle.
The year 2015 was the warmest since record keeping began in 1880, and most of the warming
occurred in the past 35 years with 15 of the 16 warmest years occurring since 2001 (Brown
et ah 2016). In particular, California is becoming hotter and drier. The 3-year period from 2012
to 2014 was the hottest and driest in California in the 100-year time frame considered (Mann
and Gleick 2015), and it was the most severe drought in California in the past 1,200 y (Grilfin
and Anchukaitis 2014). Species with small geographic ranges are more vulnerable to climate
change (e.g., Foden et al. 2013), and of particular concern are associated extreme weather events.
Because Chorro Creek bog thistle is restricted to seeps and springs in serpentine soil and rock,
a severe drought could reduce or eliminate its specialized habitat. In consideration of the life
history traits used by Anacker et al. (20 1 3), the plant is moderately to highly vulnerable to climate
change because of its relatively small geographic range and its soil and habitat specificity.
The conservation status of Chorro Creek bog thistle has improved substantially since listing
in 1994 because of an increased number of known occurrences along with an increased number
of occurrences that are protected (Table 3). Only two of nine known occurrences were protected
in 1994, whereas 10 of 21 occurrences are protected in 2016. Six of the protected occurrences
(2, 4, 14, 15, 16, 17) are in natural reserves owned by the City of San Luis Obispo. One protected
occurrence (6) is in a biological reserve owned by California Polytechnic State University. One
protected occurrence (13) is on a private property with a conservation easement to the City of
San Luis Obispo. Also, one occurrence (3) is protected on Camp San Luis Obispo because the
California Army National Guard consults with the USFWS regarding its activities as required
under the US. Endangered Species Act. These nine occurrences are on properties that range in
size from 65 to 2,271 ha. In addition, one occurrence (12) is on private property (8.1 ha) with
an open-space easement (0.8 ha) to the County of San Luis Obispo, however, we do not know
the conservation status or immediate threats.
Regarding the non-protected occurrences of Chorro Creek bog thistle, occurrences 1 and 20
are each on two private properties, and with one of each pair of landowners wishing to conserve
the plants. Occurrence 5 is in a roadside drainage ditch above underground lines, and it is at risk
by road and utility maintenance. Occurrence 7 (along Froom Creek just below mouth of Froom
Canyon) is on private property and near existing development, and potentially at risk from future
channelization and residential development. We saw no plants here in 20 1 2 and 20 1 6. Occurrence
8 is on the adjacent private property and at risk from existing development and potentially future
residential development. Occurrence 19 is on a property owned by the California Army National
Guard, and it is at risk from nearby agriculture by California Polytechnic State University.
However, we are communicating with the California Army National Guard and California
Polytechnic State University in an effort to gain protection for this occurrence. Occurrence 21
(southeast Irish Hills) is on private property and is presently safe because of its location on a
steep rocky slope and away from development. Four additional occurrences (9, 10, 11, 18) are
on private properties for which we do not know the conservation status or immediate threats.
Because there are potentially many locations with habitat on private properties and public lands
that have not been searched, it is highly likely that additional occurrences exist in San Luis
Obispo County, and possibly also in Monterey and Santa Barbara Counties.
The US. Endangered Species Act and the California Endangered Species Act have little
ability to protect the Chorro Creek bog thistle on private property. Invasive plants are a threat
or potential threat at five occurrences and native plants at two occurrences. Stochastic events
remain a threat to all occurrences. The Eurasian flower-head weevil and climate change with
severe drought are newly identified threats. In consideration of the available information, we
conclude that Chorro Creek bog thistle is still endangered. However, when using the international
STATUS OF THE ENDANGERED CHORRO CREEK BOG THISTLE
167
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STATUS OF THE ENDANGERED CHORRO CREEK BOG THISTLE
169
standards of lUCN (2012, 2014), we assign the category data deficient because of the limitations
of our data.
Recommendations
We make the following recommendations to help conserve the Chorro Creek bog thistle. The
USFWS with its partners should survey and census all 21 occurrences during one calendar
year, and special efforts should be made for gaining access to the relevant private properties
(in particular those with occurrences 1,9, 10, 11, 12 and 18). The relevant land managers and
biologists should monitor the occurrences for invasive plants, and the invasive plants should
be removed promptly. The relevant land managers should strictly control and monitor any
cattle grazing in the habitat of Chorro Creek bog thistle. Strictly-controlled cattle grazing could
possibly benefit Chorro Creek bog thistle by reducing other vegetation (invasive and native) and
by providing favorable sites for germination of its seeds. However, uncontrolled cattle grazing
in the habitat could cause severe damage. The relevant land managers and biologists should
be aware that the Eurasian flower-head weevil is a threat to Chorro Creek bog thistle, and they
should monitor for and report this invasive insect to USFWS and the San Luis Obispo County
Department of Agriculture. Additional occurrences of Chorro Creek bog thistle likely exist in
San Luis Obispo County, and possibly also in Monterey and Santa Barbara Counties. Searches
should be conducted in habitat with serpentine soil and rock in San Luis Obispo, Monterey and
Santa Barbara Counties (Figures 2, 4 and 5),
Acknowledgements
We thank the following persons for the information that they provided: LynneDee Althouse,
David Chipping, John Herr, Robert Hill, Nic Huber, Tyler Lutz, David Keil, Jody Olson, Freddy
Otte, Brad Penkala, Jake Schweitzer, Nancy Siepel and Peter Waldburger. Angela Chapman,
Douglass Cooper, Kristi Lazar, Roger Root and Connie Rutherford engaged in valuable discus-
sion. Kirk Wain produced the maps.
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STATUS OF THE ENDANGERED CHORRO CREEK BOG THISTLE
171
Appendix 1
The 2 1 known occurrences of Chorro Creek bog thistle Cirsium fontinale var. obispoense in western San Luis
Obispo County, California.
Occurrence 1. 35.62530, -121.05453 (CDFW 2016a); 107 m. This occurrence is in springs at the foot of
a serpentine landslide in the San Simeon Creek watershed (Chipping in USFWS 2014) in northwest San Luis
Obispo County. It is along San Simeon Creek, 0.3 km by road (San Simeon Creek Road) downstream of the
confluence of the North and South Forks and with the colonies on two private properties (Chipping in USFWS
2014; 12 ha; 5 ha). We viewed images of the properties using Google Earth (dated 2 April 2015) on 23 August
2016, and both were partially developed: one with an avocado farm and clearings, and the other with a house,
garage, carport and barn. Both properties are zoned for agriculture. More than 1,000 plants were reported in
1984, and 285 plants in 1993, which is the most recent information (Chipping in USFWS 2014). In the early
1990’s the Nature Conservancy assisted the private landowners with fencing to protect some colonies, and one
private landowner is protecting the plants under a voluntary agreement (CDFW 2016a). Road maintenance, water
diversions and cattle were potential threats in the 1 990’s (Chipping in USFWS 2014; Wikler and Morey in USFWS
2014). The CDFW (2016a) record states that introduced weevils are heavily infesting the flower heads, water is
being extracted from the seep, and cattle are trampling the plants. Chipping (USFWS 2014) referred to this site
as the San Simeon “Bianchi” complex. Up until 2014 this occurrence also included six sites to the west on the
adjacent private property, which subsequently became occurrence 18 (Cambria Mine near San Simeon Creek;
CDFW 2016a) because the separating distance is >0.4 km.
Occurrence 2. 35.266453, -120.682235; 35.266862, -120.682499; 35.266922, -120.682589; 35.267021,
-120.682793; 35.267148, -120.683091; 35.268814, -120.684751; 35.269886, -120.683706; 35.270353,
-120.684086; 35.270658, -120.683897; 53 to 85 m (pers. obs.). This occurrence is in Laguna Lake Natural
Reserve (152 ha) on land owned by the City of San Luis Obispo. The Chorro Creek bog thistle are in 14 seeps
spanning 635 m on a hillslope 340 m east of Laguna Lake. Most colonies are enclosed by fences, although some
colonies are expanding beyond the fences and into the landscape that is subject to controlled grazing by horses
and cattle for fuel reduction. Some fences are collapsing in 2016. More than 2,000 plants were recorded in 1999
(CDWF 2016a). Although the serpentine substrate is not conducive for most invasive species (Harrison et al.
2006), pampas grass Cortaderia became established in the habitat (and competed with Chorro Creek bog thistle),
which we and the County of San Luis Obispo removed in 2010. In 2016 and after 4 y of drought, the occurrence
appeared healthy and robust with 1,716 plants. However, at one particular seep (lower down the hillslope and
with more soil) the colony had disappeared, and invasive species (bull thistle Cirsium vulgare, rye grass Fes-
riica, vervain Verbena) predominated. We identify this seep (35.268814, -120.684751) for a needed restoration
effort. Otherwise, invasive plants were under control in 2016 and with a noteable absence of pampas grass. This
occurrence is protected. We and the City of San Luis Obispo monitor irregularly and informally.
Occurrence 3. 35.34302, -120.68178; 244 m (CDFW 2016a). This occurrence is at seeps adjacent to a tributary
of Chorro Creek (0.8 km northeast of Chorro Reservoir) on Camp San Luis Obispo (2271 ha), which is owned by
the California Army National Guard. It is protected because the California Army National Guard consults with
the USFWS (e.g., USFWS 1997, 2015) regarding its actions on the installation that may affect federally listed
species, as required by the US. Endangered Species Act. The California Army National Guard conducted annual
and formal monitoring from 1994 to 2008, then irregular and informal monitoring from 2009 to 2013, and then
formal monitoring in 2014 (Merk, pers. comm. 2016). This occurrence has experienced substantial annual variation
in numbers of reported plants, ranging from 250 (1993) to 4,644 (1999) individuals (Holland in USFWS 2014,
CDFW 2016a). We suspect that the lowest numbers reflect relatively less survey effort. Merk (pers. comm. 2016)
recorded 1,782 plants in 2014 during the most recent census. The USFWS (1997) issued a biological opinion for
controlled cattle grazing because several species of native (spikerush Eleocharis macrostachya, bulrush Scirpus)
and invasive plants (rye grass) were becoming dense in the habitat. Although controlled grazing from 1 5 April to
14 May 1998 removed <5% of vegetation, the total number of Chorro Creek bog thistle increased 68% following
the disturbance. Juvenile plants increased 727% (Mardesich and Laughlin in USFWS 2014), but established plants
decreased. Later in 2006, Magney (USFWS 2014) reported that invasive prickly sow thistle Sonchus asper had
invaded the habitat and was being removed. In 2012 the occurrence was threatened by dense vegetation in and
near the habitat, including native (salt grass Distichlis spicata, spikerush) and invasive species (purple star-thistle
Centaurea calcitrapa, bristly ox-tongue Helminthotheca echioides, prickly sow thistle; Jody Olson, Camp San
Luis Obispo, pers. comm. 2012). In 2014, Merk (pers. comm. 2016) observed excessive accumulation of thatch,
especially from native species (spikerush, sneezeweed, Helenium sp., salt grass). To manage thatch and potentially
competitive plants in and near the habitat, the California Army National Guard (USFWS 2015) intends to conduct
controlled cattle grazing during fall from 1 September to 1 5 October. Cattle grazing could possibly benefit Chorro
Creek bog thistle by reducing potentially competitive plants in and near the habitat, and by providing favorable
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SOUTHERN CALIFORNIA ACADEMY OF SCIENCES
sites for germination of seeds (Bransfield in USFWS 2014; California Army National Guard in USFWS 2014).
However, cattle grazing in and near the habitat must be strictly controlled and monitored to achieve benefits and
to minimize adverse effects (USFWS 2015).
Occurrence 4. 72 to 96 m (pers. obs.). This occurrence is at the northern edge of Irish Hills Natural Reserve
(south of Prefumo Canyon Road; 381 ha), which is owned by the City of San Luis Obispo. The colonies are in four
tributaries of Prefumo Creek: a waterfall (35.263558, -120.715975) and the creek above for >500 m (Chipping in
USFWS 2014), two nearby gullies to the southeast (150 m and 250 m distance; 5.263206, -120.714431; 35.26265,
-120.713492), and another creek further to the southeast along the Bog Thistle Nature Trail (1 km southeast of
the waterfall; 35.261344, -120.71 1639; pers. obs.). Chipping (USFWS 2014) recorded 557 plants in 1993. This
occurrence is protected. We and the City of San Luis Obispo monitor irregularly and informally. In addition, the
City of San Luis Obispo has placed interpretive signs along the nature trail, and it conducts guided hikes that
include viewing the Chorro Creek bog thistle in its habitat.
Occurrence 5. 35.264806, -120.721775; 88 m (pers. obs.). This occurrence is 547 m northwest of the waterfall
in occurrence 4. The plants are mostly in the drainage ditch along the south side of Prefumo Canyon Road, which
is owned by the County of San Luis Obispo, and also in a steep tributary of Prefumo Creek on the adjacent private
land (42 ha). Additional colonies may exist further upstream along the precipitous, rocky slope, which is covered
with dense chaparral vegetation. Numbers of reported plants were 150 in 201 1 (pers. obs.), and previously 70 in
1993, and 50 in 1986 (Chipping in USFWS 2014). In 201 1 a sign among the plants in the drainage ditch identified
underground lines (pers. obs.). The plants in the drainage ditch are threatened by road and utility maintenance.
Although this occurrence is not protected, the County of San Luis Obispo intends to manage in consideration of
the endangered plants (Kate Ballantyne, County of San Luis Obispo, pers comm. 2016). We monitor irregularly
and informally.
Occurrence 6. 35.36213, -120.70998; 335 m (CDFW 2016a). This occurrence is along the east fork of
Pennington Creek in the El Chorro Biological Reserve (81 ha), which is owned by California Polytechnic State
University. It is 1 .0 to 1 .4 km west of Whiskey Spring, which is near the headwaters of Pennington Creek. In 2012
the occurrence was in “good shape” (Chipping, pers. comm. 2012). Numbers of reported plants were 2,200 in
1993 (Chipping in USFWS 2014), and <1,000 in 1986 and 1981 (CDFW 2016a). This occurrence is protected
from cattle grazing, development, water diversions and road maintenance. California Polytechnic State University
monitors irregularly and informally.
Occurrence 7. 35.24805, -120.68683 (Chipping in CDFW 2016a; pers. obs.); 38 m. This occurrence is along
Froom Creek just below the mouth of Froom Canyon on flat land on one private property (14 ha). It is adjacent to
and east of Irish Hills Natural Reserve. CDFW (2016a) has a record of 15 plants in 1987, and Chipping (USFWS
20 1 4) reported 1 0 plants in 1 992. We saw no plants in 20 1 2 and 20 1 6, however, we have seen scattered individuals
upstream. The landscape here is especially dry and without a perennial seep or spring. We viewed images of the
property using Google Earth (dated 2 April 2015) on 23 August 2016. At least six buildings occupy the property,
and it is greatly disturbed by vehicles including bulldozers and graders. The stream bed is next to a dirt road. The
property is zoned for commercial retail and agriculture, and the City of San Luis Obispo is considering annexation
of the property for residential development.
Occurrence 8, 39 to 64 m; (pers. obs.). This occurrence is at a seep and two tributaries of Froom Creek
on one private property (30 ha) adjacent to and east of Irish Hills Natural Reserve. Chipping (USFWS 2014)
recorded 250 plants at three locations in 1993, which he referred to as Froom Ranch South, Froom Ranch North
Spring and Froom Ranch Gully Confluence. In 2016 we observed 50 plants at Froom Ranch South (35.242601,
-120.688929), 200 plants at Froom Ranch North Spring (35.243755, -120.689998) and 0 plants at Froom Ranch
Gully Confluence (35.244093, -120.687286). Previously in 2012 we observed 500, 300 and 0 plants, respectively,
at the three sites. We viewed images of the property using Google Earth (dated 2 April 2015) on 23 August 2016.
Although the property is undeveloped, the location of Froom Ranch South is 54 m downslope of a dirt road and
a building on the adjacent private property. The property with occurrence 8 and the adjacent private property are
zoned for agriculture and as rural lands. The City of San Luis Obispo is considering annexation of the property
with occurrence 8 for residential development.
Occurrence 9. 35.40309, -120.74930; 302 m (Chipping in CDFW 2016a). This occurrence is at seeps and
springs along a tributary of San Bernardo Creek on one private property (297 ha), 1 .6 to 2. 1 km southwest of
Cerro Alto Peak. The Chorro Creek bog thistle are in bogs near an inactive, open-pit chromite mine and other
excavations. Chipping (USFWS 2014) is the primary source of information, who recorded 500 plants and heavy
grazing in the bogs. We viewed images of the property using Google Earth (dated 2 April 2015) on 26 August
2016, and it was mostly undeveloped with exception of mined areas (10%). The property is zoned for agriculture.
Based on similar geology and landscape. Chipping (USFWS 2014) surmised that additional occurrences likely
STATUS OF THE ENDANGERED CHORRO CREEK BOG THISTLE
173
exist nearby to the east, including a “probable site” on two private properties 1.3 km to the southeast along a
tributary of San Bernardo Creek.
Occurrence 10. 35.30310, -120.64356; 171 m (CDFW 2016a). This occurrence is in seeps and springs on a
northeast slope above Miossi Creek (a tributary of San Luis Obispo Creek) on one private property (141 ha) that
is 0.4 km east of California Polytechnic State University and 0.8 km north of Cuesta Canyon County Park. The
primary source of information is a report dated 1 997 (CDFW 20 1 6a) with observation of > 1 ,000 plants along with
cattle in the habitat. We viev/ed images of the property using Google Earth (dated 2 April 2015) on 20 September
2016, and it was undeveloped. The property is zoned for agriculture. Based upon apparently similar landscape
features, there is high potential for additional colonies and occurrences on the adjacent and nearby undeveloped
properties.
Occurrence 11. «i35.27573, -120.60414 (CDFW 2016a). This “lost” occurrence is known from only two
specimens collected in 1987 (Consortium of California Herbaria in USFWS 2014): “on S slope of Reservoir
Canyon, 1/8 mi SE of Reservoir and Hampton Cr. junction, Reservoir Rd., 1 mi. N of San Luis Obispo off Hwy
101. 280 m.” Approximately 25 individuals v/ere observed in a spring on a north facing slope in 1987. Nic Huber
(USFWS, Ventura, pers, comm. 2011) searched for the occurrence in the Reservoir Canyon Natural Reserve in
2006 but without success. The collector (Brad Penkala, Santa Barbara, pers. comm. 2012) was unable to provide
any additional details. We suspect the occurrence is likely on a private property.
Occurrence 12, 35.256738, -120,765841; 318 m (our determination). This occurrence is at three seeps
on one private property (8,1 ha; LynneDee Althouse, Paso Robles, pers. comm. 2012 [CDFW 2016a is
incorrect] near the junction of Serpentine Lane and Prefumo Canyon Road (6 km west of the city of San
Luis Obispo), with a small open-space easement (three parcels, 0.8 ha) to the County of San Luis Obispo. Specif-
ically, the occurrence is north of benchmark 1336, north side of Prefumo Canyon Road, and west of Prefumo
Canyon. It is the only occurrence in the Los Osos Creek v/atershed and at its headwaters. Some colonies are
on the north part of the property near the boundary with the adjacent private property (Althouse, pers. comm.
2012), and some colonies are on the southern half of the property according to records of the County of San
Luis Obispo. We viewed images of the property using Google Earth (dated 2 April 2015) on 20 September
2016. It was mostly undevelope4 and with one building in its southwest corner. We suspect that Chorxo
Creek bog thistle likely occurs also on the two private properties immediately north and east because of seem-
ingly similar landfomi and geology. The property with the occurrence is zoned as rural lands. Althouse
(CDFW 2016a) recorded >4,000 plants in 2001, and the occurrence has not been visited by a biologist since
then.
Occurrence 13. 35.26189, -120.66533; 75 m (pers. obs.). This occurrence is on one private property (16 ha),
60 m northeast of Loma Bonita Drive in the central part of the city of San Luis Obispo (the urban area) with
a conservation easement to the City of San Luis Obispo (the local govemm.ent). Although the property is used
for cattle grazing, trampling is not a threat because the plants are at a seep on a steep, rocky slope. We and
the City of San Luis Obispo monitor irregularly and informally, and it has authority to conduct management
activities. We found this occurrence in 2005 at which time we estimated 300 plants. In 201 1 the colonies appeared
healthy with 500 plants. In 2015 and after several years of drought we observed at least 200 plants, which is
a reduced number. Chipping (USFWS 2014) searched this area in 1993 and saw no Chorro Creek bog thistle.
We viewed images of the property using Google Earth (dated 2 April 2015) on 25 August 2016, and it was
undeveloped with exception of communication facilities on 0.5 ha. The property is zoned for coiiservation/open
space. It is west of and adjacent to South Hills Open Space (20 ha), which is owned by the City of San Luis
Obispo, and another private property with an open-space easement (29 ha) to the City of San Luis Obispo. The
combined total area for conservation/open space of the three contiguous properties is 65 ha. This occurrence is
protected.
Occurrence 14. 35.24435, -120.70457; 267 m (pers. obs.). We found this occurrence along a tributary of
Froom Creek near an old mine in the central part of Irish Hills Natural Reserve, and we estimated at least 500
plants in 201 1 . Pampas grass was in the habitat, which we removed in 201 0 and 2011. We and the City of San
Luis Obispo monitor irregularly and informally. This occurrence is protected.
Occurrence 15. 35.25044, -120.70581; 189 m (pers. obs.). We found this very small occurrence in 201 1 along
a tributary of Froom Creek (120 m south of Froom Creek;) in the central part of Irish Hills Natural Reserve. In
2015 we counted three plants along a 200-m stretch of stream with little to no soil and debris in the stream bed
likely due to large stormflows. The location is in steep terrain on a hillslope with dense chaparral vegetation.
We suspect that a source population exists nearby upstream where the hillslope is less steep, and this should be
investigated. We and the City of San Luis Obispo monitor irregularly and informaily. This occurrence is protected.
Occurrence 16. 35.25262, -120.71388; 207 m (pers. obs.). We found this occurrence in 201 1 at Poppy Spring
(50 m from Froom Creek) in the central part of Irish Hills Natural Reserve. In 2015 and after several years of
174
SOUTHERN CALIFORNIA ACADEMY OF SCIENCES
drought, we estimated 86 plants and at which time the occupied area comprised 1 3 m x 0.5 m along a small stretch
of stream. In 201 1 we estimated 63 plants. We and the City of San Luis Obispo monitor irregularly and informally.
This occurrence is protected.
Occurrence 17, 35.278584, -120.621042; 318 to 380 m (Lutz 2013). This occurrence is on a north-facing
slope in a steep canyon immediately east of the city of San Luis Obispo in Reservoir Canyon Natural Reserve
(210 ha). It comprises four colonies in a seep and tributary of Reservoir Canyon Creek (Carter 2002, Lutz 2013),
which is a tributary of San Luis Obispo Creek. Carter (2002) observed 270 plants in 2001 and a patchy overstory
(California bay Umbellularia caiifornica, Brewer’s willow Salix breweri). Lutz (2013) counted 689 plants in
2013 along 131m of stream with an extensive overstory (Brewer’s willow, California bay, California coffee berry
Fmngula caiifornica, toyon Heteromeles arbutifolia) and shade that appeared to be adversely impacting Chorro
Creek bog thistle. He trimmed part of the overstory, and the City of San Luis Obispo is monitoring for effects.
This occurrence is protected.
Occurrence 18. 239 to 313 m (Chipping in USFWS 2014). This occurrence (Cambria Mine near San Simeon
Creek) was separated out of occurrence 1 in 2014. It is 1.1 km west of occurrence 1 on an adjacent private
property (167 ha) in a rural area zoned for agriculture. The occurrence is based upon field survey records in 1988,
1989, 1991 (CDFW 2016a) and 1993 (Chipping in USFWS 2014). Chipping (USFWS 2014) reported 792 plants
in 1993 and colonies at six sites in springs and bogs, which he designated as A Upper Spring Site (35.629594,
-121.065679), B North Roadside Spring (35.630918, -121.066138), C Stock Pond (35.634259, -121.062773),
D Stock Reservoir (35.633339, -121.062740), E Big Seep (35.633228, -121.064237), and F Cambria Mine Site
(35.628308, -121 .066337). Chipping (USFWS 2014) observed cattle in the habitat, and also weevils in the flowers
of Chorro Creek bog thistle that he suspected were Eurasian flower-head weevils. We viewed images of the property
using Google Earth (dated 2 April 2015) on 23 August 2016. Although the property is mostly undeveloped, it
contains a house, a garage, a barn, four parking areas, an orchard and two areas for livestock. Further, D Stock
Reservoir has been replaced with a lake (0.4 ha), and it appears likely that the colonies reported here no longer
exist. This occurrence is at risk from development, water diversions and cattle grazing.
Occurrence 19. 35.324094, -120.753916; 63 m (Peter Waldburger, Camp San Luis Obispo, pers. comm. 2012).
This occurrence is at a seep and tributary of Chorro Creek on a hillslope immediately southwest of the confluence
of Pennington Creek and Chorro Creek. The property ( 1 8 ha) is owned by the California Army National Guard as
part of Camp San Luis Obispo, and it is zoned for agriculture. In January 2012 the colony comprised > 1 00 plants
and appeared “healthy” when viewed across a fence line and with no evidence of cattle grazing (Waldburger,
pers. comm. 2012). David Keil (Calif. Polytech. St. Univ., pers. comm. 2012) previously observed Chorro Creek
bog thistle in this vicinity along Chorro Creek. Chipping (USFWS 2014) had searched this area in 1993 and
found no plants. We viewed images of the property with the occurrence using Google Earth (dated 2 April 2015)
on 8 August 2016, and it was mostly undeveloped. However, a small area (0.6 ha) of the property on the north
side of Chorro Creek had row crops, and likewise the adjacent property to the north that is owned by California
Polytechnic State University. This agriculture is in close proximity to any Chorro Creek bog thistle in Chorro
Creek and is not compatible with its survival. We are communicating with the California Army National Guard
and California Polytechnic State University and seeking protection for this occurrence.
Occurrence 20. 35.370836, -120.779905; 103 m (Siepel, pers. comm. 2012); 35.372239, -120.778903; 125
m (Jake Schweitzer, Berkeley, Calif., pers. comm. 2016). This occurrence is at a seep and along a tributary of
San Luisito Creek on two private properties (129 ha; 150 ha) that are north of Chorro Creek and in its water-
shed. Siepel (pers. comm. 2012) visited one property several times and estimated 200 individuals in July 2011.
She stated that the plants there were “doing well” and appeared stable at the perennial seep and spring. The
landowners identified the plants on this property in 2000. They wish to conserve the plants, and they moni-
tor irregularly and informally. Light, controlled cattle grazing occurs in and near the habitat, which appears
to benefit Chorro Creek bog thistle by reducing invasive plants (Siepel, pers. comm. 2012). Invasive species
included poison hemlock Conium maculatum in the habitat and purple star-thistle nearby, which the landown-
ers were attempting to eradicate. Schweitzer (pers. comm. 2016) visited the other property twice in 2015. He
estimated 40 Chorro Creek bog thistle along 14 m of stream, and he also observed plants across the fence
line on the adjacent property. Schweitzer saw evidence of light cattle grazing in the habitat, and he removed
several bull thistle that were growing in the habitat. We viewed images of the two properties using Google
Earth (dated 2 April 2015) on 20 September 2016, and they were undeveloped. The two groups of Chorro
Creek bog thistle are separated by 170 m. The two properties are zoned for agriculture. The Chorro Creek
bog thistle on the former property are presently safe from destructive cattle grazing, development, water diver-
sions and road maintenance, while the plants on the latter property are at risk. Based upon apparently similar
landscape features, there is high potential for additional colonies and occurrences on the nearby undeveloped
properties.
STATUS OF THE ENDANGERED CHORRO CREEK BOG THISTLE
175
Occurrence 21. 35.239909, -120.699012; 179 m (pers. obs.). We found this occurrence at a seep and small
stream (a tributary of San Luis Obispo Creek) on a steep hillslope on private property (89 ha) between Irish
Hills Natural Reserve and Johnson Ranch Open Space. We recorded 300 plants in 2012. Although cattle grazing
occurs on the property, the location with Chorro Creek bog thistle is not accessible. Pampas grass was growing
near the habitat in 2012, which we and the City of San Luis Obispo removed. We are not aware of any additional
threats. We viewed images of the property using Google Earth (dated 2 April 2015) on 24 August 2016, and
it was undeveloped with exception of a winery (2 ha) 1.1 km downsiope at the property boundary. This is the
southernmost occurrence of the Chorro Creek bog thistle.
Bull. Southern California Acad. Sci.
115(3), 2016, pp. 17^190
© Southern California Academy of Sciences, 2016
Environmental Factors Influencing Reproduction in a Temperate
Marine Reef Goby^ Rhinogobiops nicholsiij and Associated Behaviors
Michael J. Schram* and Mark A. Steele
California State University, Northridge, Department of Biology, 18111 Nordhoff St.,
Northridge, California 91330
Abstract. — The blackeye goby is a protogynous reef fish common to the northeastern Pa-
cific Ocean. While this ubiquitous species has been the focus of numerous studies, there
are several aspects of its reproductive ecology that are unknown. By directly quantifying
reproduction from digital photographs of blackeye goby nests in the field, this study aimed
to determine whether reproductive patterns were linked to 1) lunar phase or 2) ambient
water temperature; and 3) whether the behavior of gobies changed when a nearby conspe-
cific had eggs in his nest. At Santa Catalina Island, California, twenty 2.25-m^ artificial
reefs were established and stocked with similar numbers and size-distributions of blackeye
gobies during the summers of 2012 and 2013. Photographs of nests were taken weekly for
~3 months each summer. Through analysis of photographs, incubation time was found to
be more than 7 days but less than 14 days. Nests, each guarded by one male, contained
an average of 8664 eggs, in an area of 43.8 cm^, with 215 eggs cm“^. Blackeye gobies
laid eggs during all lunar phases and the number of eggs produced was not related to lunar
phase. Reproductive output, however, was negatively correlated with water temperature,
with populations on reefs that experienced cooler temperatures producing more eggs. The
presence of eggs in a nest had little effect on behavior of blackeye gobies on that reef. Ad-
ditional observations made outside of summer months indicated that blackeye gobies can
reproduce year-round in southern California. These results suggest a reproductive strategy
aimed at maximizing total reproductive output by spreading the risk of reproductive failure
throughout the year rather than optimizing the timing of reproduction.
In marine animals with pelagic larvae, factors that affect recruitment of settlers into popula-
tions are typically better understood than factors that affect reproductive output. This is because
it is generally easier to observe recruits than it is to observe reproduction. Thus, much of what
we know about reproductive patterns of marine animals is inferred from temporal patterns of
recruitment, rather than direct observations of reproduction. For example, reproductive patterns
of fishes with pelagic larval phases are often reconstructed from recruitment surveys combined
with otolith-based aging. This approach, however, can mask the actual patterns of reproductive
output due to high and variable mortality rates during the larval phase (Carr and Syms 2006;
Johnson 2008).
As an example, lunar patterns in recruitment could be driven by reproductive timing or by
differences in larval delivery or survival that have a lunar basis. Synchronizing larval release
with a particular lunar phase that exposes larvae to favorable environmental conditions may
provide fitness benefits and has been observed in a wide array of marine taxa (Middaugh 1981;
Robertson et al. 1990; Levitan et al. 2004; Fox 2013). Pelagic larvae are thought to be more
conspicuous to visual predators during full moons when lunar radiance is greatest (Hobson et al.
* Corresponding author: Michael JSchram(ggmaiI. com
176
ENVIRONMENTAL FACTORS INFLUENCING BLACKEYE GOBY REPRODUCTION
177
1981); however, photopositive larvae may swim toward the surface during full moons, avoiding
predator filled reefs (Thresher 1984). Additionally, internal waves, associated with changes in
tidal amplitude driven by lunar phase are thought to influence the probability and timing of
larval exposure to suitable habitat and levels of intraspecific competition (Kingsford and Choat
1986; Shanks 1986; Levinton 2009).
Another factor known to affect reproduction of marine fishes is temperature (Abbott 1969;
Smyder and Martin 2002; Sims et al. 2004). Generally, embryo and larval development is
faster in warmer waters (Pauly and Pullin 1988; McCormick and Molony 1995), reducing
incubation time (Ryland and Nichols 1975), and pelagic larval duration (O’Connor et al. 2007).
Reproducing during periods of warm water can improve larval survivorship by increasing
larval growth rates shifting prey out of size ranges that predators are capable of consuming
(the ‘‘growth-mortality” hypothesis; Anderson 1988). Conversely, nutrient availability is often
inversely related to water temperature (Dayton et al. 1998) and therefore larval growth may
increase when water temperature is low and food (e.g., zooplankton) is abundant.
Alongside abiotic factors, behavior often plays a significant role in reproductive success. In
fishes, demersal eggs are typically defended by the male and less often by the female or both
parents (DeMartini and Sikkel 2006). Behavioral changes, such as increased aggression (i.e.,
nest defense) and nest maintenance, improve hatching success; however, they may occur at the
cost of foraging, predatory avoidance, or further courtship. Population density (Warner and
Hoffman 1980) and reproductive territoriality (Hoffman 1983) may further modify behavioral
trade-offs. Thus, while altered behavior of a nesting male may improve egg survivorship, it
may detract from future mating opportunities by allowing increased courtship and foraging by
competing subordinate individuals.
The majority of protogynous (female-to-male sex-change) species, including the study
species, exhibit a size-based social dominance hierarchy whereby dominant individuals in-
fluence the behavior of subordinate individuals (Cole 1984; Ross 1990). Specifically, alpha
males dominate and socially repress growth of nearby individuals, through increased energetic
expenditure and decreased foraging rates of subordinates, to maximize their competitive edge
and reproductive opportunities (Helfman et al. 2009; Munday et al. 2009). Altered behavior of
the alpha male, such as increased nesting behaviors at the cost of intraspecific aggression, could
reduce social repression of subordinate individuals.
The blackeye goby {Rhinogobiops nicholsU) is a protogynous fish that occurs from British
Columbia, Canada to central Baja California, Mexico where it is closely associated with rocky
reef habitat (Love 2011). It is common in the waters of southern California. The ubiquity
and small size of this species has resulted in its widespread use as a model study species to
address ecological questions (e.g. Breitburg 1987; Steele 1996; Yong and Grober 2013), While
an extensive body of literature has been compiled on this species over the past 50 years, (e.g.
Ebert and Turner 1962; Wiley 1973; Cole 1983), several aspects of the reproductive ecology
of this species are still unknown. Ebert and Turner (1962) briefly described blackeye goby
reproduction; Wiley (1973) documented food and nesting habits, morphometries, population
structure, and social behavior; Cole (1983) determined that this species exhibits protogynous
hermaphroditism; and Breitburg (1987) showed that male reproductive success was limited by
the availability of suitable nest sites.
Male blackeye gobies compete for territory that encompasses the territories of multiple
females (Cole 1984) through a number of behavioral displays (Wiley 1973). Because blackeye
gobies exhibit a size-based social dominance hierarchy, larger males tend to have greater success
at acquiring and defending territories that provide opportunities to mate with nearby females
(Cole 1 983). Male blackeye gobies establish and defend a nest within their territory by digging a
178
SOUTHERN CALIFORNIA ACADEMY OF SCIENCES
burrow in sand under overhead rock (Ebert and Turner 1962; Wiley 1973). Females lay adhesive
eggs on the rock ceiling of the burrow and the male defends and maintains the brood of eggs
until they hatch (Ebert and Turner 1962). Larvae are planktonic for 40-76 days before settling
to suitable reef habitat (Block 2011).
It is not known, however, whether the reproductive patterns of blackeye gobies change in
response to environmental or social stimuli. We directly measured reproductive output by em-
ploying artificial nests, an approach used in studies on other small, reef-dwelling fishes (e.g.
Knapp et al. 1995; Samhouri 2009; Forrester et al. 2010). We aimed to (1) determine whether
blackeye gobies time reproduction with lunar phase, (2) investigate links between reproductive
output and temperature, and (3) determine whether the presence of eggs in a nest influences the
behavior of nearby conspecifics.
Materials and Methods
General Methods
To evaluate factors influencing reproduction in blackeye gobies, experimental populations
were established on twenty rock-rubble reefs in Big Fisherman Cove, Santa Catalina Island,
USA (33°26'42"N, 118°29'8"W) during the summers of 2012 and 2013 (Fig. lA). Each reef
was 2.25 m^ and constructed of ~60 L of rock placed on a PVC frame lined with plastic mesh
to keep the rocks from sinking into the sand. Reefs were built on a sand plane at 10-13 m
depth, and were 1 0 m from any other reef structure to minimize movement of fish among reefs.
To minimize mortality, each reef was covered with a predator exclusion cage (3.4 and 3.8-cm
plastic mesh in 2012 and 2013, respectively). To investigate the influence of temperature on
reproduction, six iButton temperature loggers were deployed throughout the reef array in 2013.
These recorded bottom temperatures hourly from July 19 to September 13, 2013.
Each reef was stocked with a similar number, size distribution, and sex ratio of blackeye gobies
as determined from surveys on natural reefs (Cole 1984, Love 2011, pers. obs.). Densities were
16 ± 4 individuals per 2.25-m^ reef comprised of 5 di 2 males, 7 ± 2 females and 4 ± 2
juveniles (mean ± SD, n = 20). Gobies were collected with dip nets by SCUBA divers on
natural reefs between Lion’s Head Point (33°27'08"N, 118°30'05"W) and Little Geiger Cove
(33°27'32"N, 1 18°30'59"W). Sex was determined from genital papillae, an accurate indicator
of functional sex and maturity in gobiids (Cole 1983, Cole and Robertson 1988).
Reproductive Output
Reproductive output was quantified via photographs of eggs in artificial nests, using methods
similar to those of Forrester et al. (2010) who studied a similar species of goby. Inverted
terracotta potting saucers were used as artificial nest sites. A small opening was cut along one
edge of each saucer (Fig. 2A), which provided easy access for males and promoted their use
over natural rocks. Three saucers were placed on each reef (Fig. 1 B). During summer months
(July-September), saucers were checked weekly for the presence of broods of eggs, and all
broods were digitally photographed. Additionally, from October 2013 to late March 2014, nests
were checked and photographed monthly to determine if reproduction was occurring during
autumn, winter, or spring.
The digital images were analyzed in Image J (Abramoff et al. 2004) to estimate the number
of eggs in each brood. Images were set to scale, total brood area was measured, and egg counts
were made in five l=cm^ subsamples. Egg density appeared to be uniform, and therefore the
total number of eggs in each brood was estimated as the product of the average density of eggs
in the five subsamples and total brood area.
ENVIRONMENTAL FACTORS INFLUENCING BLACKEYE GOBY REPRODUCTION
179
Fig. 1 . Artificial reef design. A) Reefs were constracted along the southern side of Big Fisherman Cove in
two parallel lines. B) Each artificial reef was composed of four interconnected sub-reefs positioned evenly v/ithin
the 2.25-m^ plot to maximize habitable space. Tliree inverted terracotta potting saucers served as artificial nests
on each reef. C) Reefs were categorized by depth, shallow (~10 m) or deep (~13 m), and position relative to the
back of the cove.
Behavior
Behavioral observations were conducted weekly for 7 weeks beginning on My 8, 2012 to
determine if behaviors changed when broods of eggs were present on reefs. The behaviors
of three classes of blacke^/e goby, males, females, and juveniles, were recorded. Two divers
visited each reef for 6 mmuies and each diver observed three fish, one in each class. The first
minute of each observation period was spent identifying focal individuals and allowed fish to
acclimate to diver presence, and the remaining 5 minutes were spent observing the behaviors
of all three individuals. Due to the sedentary nature of the study species, it was not difficult
for each diver to independently monitor three fish simultaneously. Large males were targeted
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SOUTHERN CALIFORNIA ACADEMY OF SCIENCES
Fig. 2. Terracotta saucers were used as artificial nest sites. A) A small slot cut along one edge provided easy
access for males, promoting use of artificial nests over natural rock. B) Close-up photo of a single brood of eggs
on the underside of nesting saucer. Individual eggs are easily identifiable. The scattered eggs that appear white are
dead, likely because they were not fertilized or succumbed to microbial infection.
because of their social dominance and influence on conspecific behavior. They were easily
identified by their size [>1.5 cm standard length (SL)], black pelvic disc, and close proximity
to a nesting saucer. Females were smaller (4.0-7. 5 cm SL) and lacked the obvious black on
their pelvic disc. Juveniles were smaller than adults (<4.0 cm SL) and were often found at reef
margins, likely displaced from optimal reef habitat by territorial adults. The frequency of four
focal behaviors defined by Wiley (1973; Table 1), were recorded: aggression, courtship, nesting,
and foraging. Divers were unable to communicate to each other which fish they had chosen to
Table 1 . Behaviors recorded, as described by Wiley ( 1 973).
Behavior
Description
Aggression
Flaring fins and/or gaping mouth
Chasing
Courtship
Flaring fins while undulating body outside nest opening
Quick rushes in and out of nest
Nesting
Removing sediment or growth from inside nest
Body undulations within nest entrance aerating eggs
Foraging
Short bursts into the water column picking at particles
Sifting mouthfuls of sediment for infaunal organisms
ENVIRONMENTAL FACTORS INFLUENCING BLACKEYE GOBY REPRODUCTION
181
observe, therefore, to avoid pseudoreplication, the average of the two divers’ observations of
each class were used for statistical analyses.
Temperature
Six temperature loggers (IButton thermocron, model DS1921G) were placed throughout the
array of reefs to explore potential effects of temperature on reproductive output during 2013.
The loggers recorded temperature every hour for nearly two months (July 19 - September 13,
2013). The iButtons were waterproofed inside a pair of male and female end caps (3/4 inch
schedule 40 PVC) with Teflon thread tape and included a small dehydration packet to absorb
moisture. Temperature loggers were placed in 6 evenly spaced positions relative to the back of
the cove (near, middle, and far) and at different depths (shallow or deep; Fig. 1C).
Statistical Analyses
To test for any lunar pattern in blackeye goby reproduction, we used two-way, mixed-model
permutational analysis of variance (PERMANOVA) to compare weekly reproductive output
among the four lunar stages (new, 1®* quarter, fiill, and 3^^^ quarter) over two full lunar cycles
during July and August, 2012 using reefs as replicates, which were sampled repeatedly. The
factors in the model were lunar stage (fixed) and reef (random). Univariate PERMANOVA
was used rather than parametric ANOVA because the data were badly non-normal due to a
preponderance of zeros (almost half of the observations). An a priori comparison of spring (foil
and new moons) and neap (first and last quarter moons) tides was conducted to test for any
influence of tidal amplitude. PRIMER v6 with the PERMANOVA + add on was used for all
permutational analyses.
We had too few temperature loggers to test whether reproduction on each reef was related to
temperature on it, so instea4 we tested whether reproductive output at reefs in the vicinity of
each of 6 temperature loggers {n = 3-4 reefs) was correlated with differences in temperature
among the 6 positions. Two-way ANOVA was used to test for (1) differences in daily bottom
temperature and (2) average reproductive output per week between depths and among positions.
Assumptions of normality and homogeneity of variances were met for mean daily temperature
and reproductive output after squareuoot transformation. We tested for a correlation between
reproductive output and wates n- rupv- unme in the 6 portions of the study area using a Spearman
rank correlation, because the idaiienship appeared to be nonlinear. SYSTAT 13 was used for
these analyses.
We tested whether blackeye goby behavior differed when a brood of eggs was present on a
reef. Egg presence was based on nest photos taken 2-3 days prior to the behavioral observations.
Permutational multivariate analysis of variance (PERMANOVA) was used to test for differences
in behavior, with egg presence in a nest and fish class (male, female, or juvenile) as the two
predictor variables and the rates of aggression, courtship, nesting, and foraging behaviors as
the multivariate response variables. Rates of behaviors were normalized (mean subtracted and
divided by the standard deviation) before constructing a dissimilarity matrix with them using
Euclidean distances. PERMANOVA was used rather than MANOVA because the data failed to
meet the assumptions of normality.
Results
Reproduction occurred in all months that populations of blackeye gobies were on the reefs,
from July to March, with eggs clearly visible within saucer nests (Fig. 2B). Broods contained an
average of 8664 ( ± 349) eggs, in an area of 43.8 ( ± 1.9) cm^, with an average density of 215
182
SOUTHERN CALIFORNIA ACADEMY OF SCIENCES
Fig. 3. Sequential weekly photographs of a single brood of eggs in a nesting saucer. A) Eggs in the recently
laid brood appear pink/orange and the density of eggs is relatively uniform. B) Changes in color are seen within
7 days and close inspection reveals developed embryos inside eggs. C) After 14 days, all surviving larvae have
emerged and the nest surface is bare.
( ±4) eggs cm“^ (mean ± SE, n = 240). As described by Ebert and Turner (1962), recently
laid eggs appeared pink/orange (Fig. 3A), transitioning to transparent as they developed (Fig.
3B). The eyes of developing embryos were visible in late-stage eggs, allowing differentiation
of several clutches in a single nest. Identifiable individual clutches were observed in sequential
photos taken a week apart on several occasions (Fig. 3), establishing a minimum incubation
period of 7 days. Assuming eggs hatched within 24 hours after the second photograph of the
ENVIRONMENTAL FACTORS INFLUENCING BLACKEYE GOBY REPRODUCTION
183
10000
8000
c
o ^
’’S ? 6000
3 o
■O g
S g 4000
Q.S
0 £
2000
Full
0
Jull Julie Jul31 Aug 15
Date
New
Aug 31
Fig. 4. The average number of eggs produced by reef populations (solid) relative to lunar phase (dashed)
during two months in 2012. Cyclical patterns, coinciding with lunar phase or tidal amplitude were not apparent
(see Results). Error bars represent ± 1 SE.
sequence, or 24 hours prior to the third photograph, then egg incubation time was between 8
and 13 days.
Blackeye gobies did not appear to time reproductive effort with any particular lunar phase,
producing similar numbers of eggs during all four lunar phases (Pseudo-i^3,57 = 0.69, p = 0.56,
Fig. 4) and a similar number of nests during all four phases (27-33 nests). Moreover, reproductive
output was unrelated to tidal amplitude, with similar numbers of eggs produced (mean ± SE:
4461 zh 607 vs. 5461 ± 673 eggs; Pseudo-F’ij9 = 1.81,/? = 0.18) and similar numbers of
active nests during spring and neap-tide periods (56 and 66), respectively.
Reproductive output was negatively correlated with water temperature (Spearman rank cor-
relation: r = —0.89,/? = 0.02), being higher on reefs in cooler portions of the study area than in
warmer areas. This relationship appeared to be non-linear, with similar high reproductive output
on reefs with average temperatures below 18°C, declining on reefs with average temperatures
between 1 8 and 19°C (Fig. 5). Deeper reefs were colder on average than shallower reefs, as were
reefs closer to the mouth of the cove compared to those in the middle or near the back (depth:
^1,336 = 19.77,/? < 0.001; position: F2336 = 13.77,/? < 0.001; depth x position interaction:
^2,336 = 2.56, p < 0.08; Fig. 6a). Reproductive output, however, did not differ statistically
between depths or among positions (depth: F1J4 = 2.34, p = 0.15; position: F2J4 = 0.08, p =
0.92; depth x position: ^2,14 = 0.35,/? = 0.71) due to high reef-to-reef variation (Fig. 6b).
The presence of a nest with eggs on a reef did not alter the multivariate behavioral response of
fish living on that reef (Egg Presence x Fish Class interaction: PseudO“F2,4i4 = 0. 1 8,/? = 0.99;
Egg Presence: Pseudo-Fi3i4 = 1.06,/? = 0.35; Fig. 7). Despite the absence of a statistically
significant difference in the multivariate behavioral response between times with eggs present
vs. absent, males foraged 41% less when eggs were present (mean ± SE: 0.55 ± 0.08 vs. 0.94
± 0.18 bites per 5 min.; univariate PERMANOVA: Pseudo-F’ij38 = 5.24, p = 0.03). Regardless
of egg presence on a reef, behavioral rates differed among fish classes (Fish Class: Pseudo~F2,4i4
= 65.34,/? = 0.001). Males were the most aggressive, females were intermediate, and juveniles
were the least aggressive (Fig. 7). Feeding rates were the opposite, with juveniles feeding the
most and males the least. Males courted and nested, whereas females and juveniles did not.
184
SOUTHERN CALIFORNIA ACADEMY OF SCIENCES
5000
4000
0 L j™_ -1 1
17 17.5 18 18.5 19
Temperature (®C)
Fig. 5. Negative relationship between blackeye goby egg production and temperature. Reef Depth: closed =
deep, open = shallow. Reef position: circle = far, triangle = middle, square = near. See Results for statistical
details.
Discussion
Although reproductive lunar synchrony is thought to be prevalent in tropical habitats (Johannes
1978), it is relatively uncommon in temperate waters. Blackeye gobies appear to follow that
trend, as they did not exhibit any noticeable lunar or tidal cycle in their reproductive activities.
Thresher (1984) noted several hypotheses that would select for lunar reproductive patterns in
marine organisms, two of which could explain the lack of lunar synchrony in blackeye gobies.
One hypothesis is that reproduction is timed so that larvae hatch when food densities are high,
which could have a lunar pattern. The other hypothesis is that lunar phase is a convenient way
to synchronize reproductive efforts among numerous individuals (including those of multiple
species), reducing larval mortality by swamping their predators. Johannes (1978) noted that
temperate reef residents experience lower larval predation than tropical reef residents, which
might result in lower selection for lunar synchrony of reproduction in temperate species like the
blackeye goby. Similarly, a lack of lunar pattern in larval food abundance could explain a lack
of lunar pattern in reproduction. Instead, continuous reproduction without lunar pattern might
maximize lifetime fitness.
The absence of lunar synchrony might also be attributable to the long and variable larval
duration of the blackeye goby. During their roughly two-month-long pelagic phase (Block 2011),
larvae would experience several lunar cycles. Thus, timing reproductive effort to a particular
lunar phase may result in negligible fitness gains. The large range of size at settlement in the
blackeye goby (16 to 25 mm SL; Watson 1996), coupled with a variable pelagic duration,
suggests variation or flexibility in larval growth rates and settlement potential. Larvae have been
known to delay metamorphosis (McCormick 1 999) despite having reached adequate settlement
size (Victor 1986), presumably increasing exposure to potential settlement habitat. A similar
ENVIRONMENTAL FACTORS INFLUENCING BLACKEYE GOBY REPRODUCTION
185
Reef Depth
Fig. 6. A) Average egg production of blackeye gobies pooled over eight weeks for each reef depth and position
combination during 2013. Differences in reproduction between depths or among positions were not statistically
significant, (k — 24 or 32 for each group). B) Average temperature during the same eight weeks for each reef
depth and position combination. Deep reefs and reefs farther from the back of the cove were colder than shallower
reefs and reefs closer to the back of the cove (n = 57 days per bar). Error bars represent ± 1 SE (see Results for
statistical details).
186
SOUTHERN CALIFORNIA ACADEMY OF SCIENCES
0.75
0.5
Male
■ Eggs Absent
□ Eggs Present
0.25
0
j
Aggression Courtship Nesting Foraging
Behavior
Fig. 7. Rates of behavioral expression when eggs were present in a nest on a reef or not, in the three classes of
blackeye goby; male, female, and juvenile. The presence of eggs in a reef nest did not influence behaviors except
male foraging (see Results). Means ± 1 SE are shown {n = 140 observations per bar).
process may exist in blackeye gobies, promoting continuous reproduction, which supplies a
pelagic larval stock that is capable of delayed and selective settlement, thus reducing risk of
reproductive failure.
Temperature varied significantly within our array of reefs, and reproductive output reflected
differences in temperature, decreasing with increasing temperature. Deeper reefs and reefs closer
to the mouth of the cove were colder than shallower reefs and those nearer the back of the cove.
These differences in temperature are due to the amount of time that those areas spent under the
thermocline (MJS and MPiS, personal observations). Differences in temperature are correlated
with differences in nutrient concentrations (Dayton 1985; Dayton et al. 1998) and perhaps
food availability (e.g., zooplankton). Therefore, differences in reproduction related to water
temperature might not be driven by temperature differences per se. Nevertheless, temperature
and day length are generally recognized as the two of the most widespread environmental cues
for seasonal reproduction, and within the reproductive season, there may be thermal optima
(Shrode and Gerking 1977; Gerking et al. 1979). The wide geographic range (British Columbia
to Baja California) and depth range (intertidal to 80 m; Love 201 1) occupied by the blackeye
goby indicates that it is adapted to a wide range of temperatures, but reproduction may be
reduced at warmer times or places.
ENVIRONMENTAL FACTORS INFLUENCING BLACKEYE GOBY REPRODUCTION
187
We documented biackeye goby reproduction during each month from July through late
March, When coupled with Ebert and Turner’s (1962) account of nesting from April through
October, there is documented evidence for year-round reproduction by the biackeye goby in
southern California, supporting claims of year-round reproduction by Love (2011), Breitburg
(1987) observed reproduction only between March and October at her study site near Santa
Barbara, California, It is possible that reproduction occurs year-round in warmer locations
but only seasonally in cooler areas. Temperature is known to affect both incubation time
(Lasker 1964; Miranda et al 1990) and larval growth rates (O’Connor et a!. 2007) which
may help explain the seasonality observed in populations experiencing cooler average annual
temperature.
Our estimates of brood size were more than five times greater than the 1700 eggs in a
single nest reported by Ebert and Turner (1962). Based on Wiley’s (1973) estimation of female
fecundity ranging from 3274 to 4788 eggs (n = 4 females), a minimum of two females would
be necessary to account for the 8663 eggs per nest recorded in this study; however, female
sizes were not included with Wiley’s estimates. Since female fecundity is known to increase
exponentially with body length (Duarte and Alcaraz 1 989) it is possible that a single large female
could produce the average number of eggs observed here. Conversely, the large number of eggs
per nest found in the present study could be the product of multiple females spawning in a single
nest over a short period of time. If female biackeye gobies exhibit similar nesting preferences
and habits as a number of damselfishes that have been studied, multiple females may lay eggs in
a single nest over a short period, producing what appears to be a single large clutch (Sikkel 1 989;
Knapp et al. 1995). Love (201 1) stated that males may defend the clutches of up to 6 females;
however, one or two females appears to be typical, which is in line with a reported population
sex ratio of 1.7 females per male (Wiley 1973). Although more than one clutch in a single nest
was observe^ ( ^ m sr veral occasions (based on the presence of non-contiguous clutches and eggs
of different sMges), the majority of nests appeared to contain a single clutch.
The exaci mi^ubation period for biackeye goby eggs could not be determined from our once-
a-week photos, but it must have been more than 7 days and less than 14. While increasing the
frequency of nest observations could provide a more accurate estimate of incubation time, the
consistent disruption necessary might also result in nest abandonment or filial cannibalism by
guarding males, biasing estimates low. An attempt was made to passively observe reproduction
in clear acrylic aquaria equipped with flow through seawater, but no eggs were produced in
either of two lab populations over a month. Aquaria were set up similar to the small reefs used
in the field (i.e,, rock rubble collected under water and artificial nesting saucers), but sand was
not include4 as it would have obscured the view of the nest.
Behaviors of males, females, and juveniles were mostly unaltered by the presence of eggs on
the. reef Surprisingly, rates of aggression and nesting behavior by males did not change despite
grrndm*;' nest containing eggs. Foraging rates of males guarding eggs were, however, about
40% lower than when eggs were absent, "^fiiile eggs were present in the nest, males continued
to court females, despite the potential for damaging or dislodging eggs already in the nest. The
costs and benefits of the behaviors we quantified may depend on context, however. For example,
work on other fishes has shown that territoriai defense can be affected by population density
(Warner and Hoffman 1980); and male foraging rates can be influenced by male territorial
strategies (Hoffman 1983). Although we stocked our artificial reefs with densities reflecting
those on natural reefs at Catalina at the time (^6 individuals MJS pers, obs.), higher
densities are sometimes observed in nature, e.g., up to 20 individuals (Love 2011; Steele,
unpublished data). Behavioral responses to the presence of nests with eggs might differ in those
higher-density populations. More artificial nest sites were present on our reefs than were used.
188
SOUTHERN CALIFORNIA ACADEMY OF SCIENCES
indicating this resource was not limited, which could alleviate density-dependent competition
for preferred nesting space.
Results from this study indicate that blackeye gobies reproduce year-round, and without
any lunar or tidal patterns. These findings suggest this species maximizes reproduction over a
protracted period and it employs a bet-hedging strategy by spreading out reproductive efforts,
thereby reducing the risk of reproductive failure. Whether this reproductive strategy is employed
by the blackeye goby throughout its very broad geographic range is an interesting question that
is amenable to study because reproductive output in this species is relatively easy to measure
using the methods described in this paper.
Acknowledgements
We thank S. Ranson, C. Paterson, and N. Gan for field assistance. We appreciate the logistical
support provided by the staff of the University of Southern California Wrigley Marine Science
Center field station. Drs. M. Adreani and L. Allen provided useful advice, and they and three
anonymous reviewers provided helpful comments on drafts of this manuscript. This research was
supported by funding from the CSU Northridge Association of Retired Faculty, CSUN Graduate
Thesis Support, the CSUN Peter Bellinger student research award, CSU-COAST, Sigma Xi, the
use Rose Hills Foundation Summer Fellowship, and the National Science Foundation (OCE-
1437571). This is contribution # 252 from the Wrigley Marine Science Center.
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Bull. Southern California Acad. Sci.
115(3), 2016, pp. 191-197
© Southern California Academy of Sciences, 2016
The Largemouth Blenny^ Labrisomm xant% New to the California
Marine Fauna with a List of and Key to the Species of LabrisomidaCj
Clinidae^ and Chaeeopsidae found in California Waters
Milton S. Love/* Mianne Kalman Passarelli/ Ben Cantrell/ and Philip A. Hastings^
^ Marine Science Institute, University of California, Santa Barbara, CA, 93106
^Cabrillo Marine Aquarium, 3720 Stephen M. White Drive, San Pedro, CA, 90731
^ North American Native Fishes Association, Peoria, IL, 61614
^Marine Biology Research Division, Scripps Institution of Oceanography, University of
California, San Diego, 9500 Gilman Drive #0208, La Jolla, CA, 92093
We report here on the first observations and capture of breeding populations of the largemouth
blenny, Labrisomus xanti Gill, 1 860 (Family Labrisornidae) in California marine waters. We
also provide a list of those members of the closely related families Labrisornidae, Clinidae, and
Chaenopsidae that are found off California with a key to these species.
The first observation of this species in California waters occurred on 15 July 2015, when
Callie Mack and Tara Howell observed one individual in about 5 m of water in front of the
Marine Room Restaurant (La Jolla Shores) (32°5rN, 117°16*W) among low lying rocks.
Ms. Mack described the fish as having “a blenny-like profile, about 6 or 7 inches long (the
length of my hand), bright red and covered with many small blue spots, and a partial bright blue
ring at the base of each eye. It was perched in a rock crevice on its red pelvic fins. Pectoral fins
were red shading to yellow. Dorsal fin was also bright red with blue spots on the foredorsal [sic]
part. It had 3 rows of small for-like (or eyelash-like) cirri, also covered with blue spots, on the
top of its head, one set just below each eye, and 2 rows above the eyes on the forehead. It was
either curious or territorial (probably the latter); kept coming out of its crevice, sitting in the
open for a few moments, then going back in.”
Ms. Mack and Ms. Howell returned to the same general area on 19 July 2015 and observed
at least four different individuals, two on each dive and all at a bottom depth of 3-4 m. On
this occasion she provided us with a number of images of one of the individuals that was red
and she described it as quite territorial as it chased off a California sheephead and lunged at
Ms. Howell’s video camera. From Ms. Mack’s initial description, and her subsequent pho-
tographs, we determined that these fish were most likely the largemouth blenny, Labrisomus
xanti and that the red individuals were breeding males (Thomson et al. 2000),
Additional observations were made of this species at the same general site on 11 and 19
August 2015 by Rogei Uziin who observed at least five unique individuals. Similar to previous
sightings, he observed the fish at depth of 3-4 m on low-lying rocks. However on these days,
Mr. Uzun observed what was likely mating behavior and nest guarding. On both 1 1 and 1 9
August, he observed, photographed, and video recorded a bright red individual (Fig. 1) courting
and apparently fertilizing the eggs of two drabber individuals (Fig. 2). This male then guarded
and aerated the apparent eggs. Similar courtship and parental behaviors are known for other
species of the genus Labrisomus (Gibran et al. 2004).
Janna Nichols made the first observation of this species known to us away from the La Jolla
area on 31 October 2015 off Casino Point at Santa Catalina Island (33°20.9’N, 1 18°194*W) in
* Corresponding author: love@lifesci.ucsb.edu
191
192
SOUTHERN CALIFORNIA ACADEMY OF SCIENCES
Fig. 1. Male largemouth blenny, Labrisomus xanti, photographed near La Jolla, California, August 2015.
Photograph by Roger Uzun.
about 7 m of water among rocks. Based on the images Ms. Nichols provided, the Casino Point
fish (brownish-gray) may have been a female or a male (mature males lose their red coloration
during the non-reproductive season — Mark Steele, pers. comm, to M. L.). Ms. Nichols notes
that she likely saw another, similarly colored, individual later in the day otf Torqua Springs
(33°23.0’N, 1 18°21.6'W) about 5 km up northwest of Casino Point.
Through December, recreational divers continued to see at least several individuals on the
shallow Marine Room reefs. However, we received no reports of L. xanti sightings from unique
areas until Dan Richards and party found several fish, again at Catalina Island, but this time
further west of the previous sightings. Mr. Richards, along with Steve Lee and Jessie Altstatt,
saw one individual among cobbles in 5-6 m in Big Fisherman Cove (33°26.7'N, 1 1 8°29. 1'W) on
2 May 2016. On 4 May 2016, Mr. Richards saw an additional fish under a small rocky overhang
in 3 m of water at nearby Isthmus Reef
Lastly, Mark Steele informs us that, as of late summer and early fall 2016, “I searched a band
that was approximately 1 50 m long and 3 m wide in 1.2 - 2 m depth in the back of Big Fisherman
Cove and counted 19 different individuals. This was not an exhaustive search and this species
is pretty shy, so Tm sure 19 is an underestimate of true abundance in that area.” He goes on to
note that an associate had also seen this species at several other sites around the island.
Fig. 2. Female (left) and male (right) largemouth blennies, Labrisomus xanti, exhibiting breeding behavior,
August 2015, La Jolla, California. Photograph by Roger Uzun.
LABPJSOMUS XANTl, NEW TO CALIFORNIA
193
Table 1 . Members of the families Clinidae, Labrisomidae, and Chaenopsidae from California waters with
notes on their maximum sizes, and geographic and depth ranges. CAS = California Academy of Sciences; LACM
= Los Angeles County Museum of Natural History; SIO — Scripps Institution of Oceanography Marine Vertebrate
Collection. Min. = minimum depth observed; max. = maximum depth observed. D == dorsal-fin elements; A
” anal-fin elements; Pect. ~ pectoral-fin rays; Pelvic = pelvic-fin rays; LLs = lateral line scales; LLp = pored
lateral line scales; GR = gill rakers, lower + upper; GRt = total gill rakers; Vert. = total vertebrae.
Family Clinidae — Kelp Blennies
Gibbomia elegam (Cooper, 1864), Spotted Kelpfish. To 16 cm TL (Miller et al 2008). San Francisco Bay
(CAS 215456), northern California to Bahia Magdalena, southern Baja California, including Isla
Guadalupe (Eschmeyer and Herald 1983). Intertidal and to 56 m (min.: Wells 1986; max.: Eschmeyer and
Herald 1983). D XXXI-XXXX5-8; A IMII,21-25; Pect. 1 1-13; Pelvic 1,2-3; LLp 62-71; GR 4-5 +
8-12 := 12-16; Vert. 47-49. The spotted kelpfish was mistakenly given the name Gibbonsia evides by
Eschmeyer (1998); for explanation see Nelson et al. (2004:243).
Gibbonsia metzi Hubbs, 1927. Striped Kelpfish. To 23.5 cm TL (Miller and Lea 1972). Vancouver Islan4
British Columbia to Punta Rompiente, central Baja California (Miller and Lea 1972). Intertidal, including
tide pools, and to 18 m (min.: Eschmeyer and Herald 1983; max.: LACM 35689-2). D
XXXIV-XXXVII,7-10; A 11,24-29; Pect. 1 1-13; Pelvic 1,3; LLp 64-71; GR 3-4 + 7-8 = 1 1; Vert.
50-53.
Gibbonsia montereyemis Hubbs, 1927. Crevice Kelpfish. To 13.9 cm SL (SIO 80-19). Vancouver Island,
British Columbia (Lamb and Edgell 2010) to Isla Guadalupe (SIO 60-15), Bahia San Carlos (SIO
52-215) and Isla Cedros, Islas San Benito, and Isla Natividad, central Baja California (Ramirez- Valdez
et al. 2015). Intertidal and to 37 m (min.: M, L., unpubl. data; max.: I Carroll, pers. comm, to M. L.).
Gibbonsia erytkra Hubbs, 1952, is a junior synonym (Stepien and Rosenblatt 1991). D
XXXIV~XXXVI,5-8; A II, 23-28; Pect. 1 1-13; Pelvic 1,3; LLp 61-70; GR 2-5 + 7-10; Vert. 49-51.
Heterostichus rostratus Girard 1854. Giant Kelpfish. To 61 cm TL (Miller and Lea 1972). British Columbia to
Cabo San Lucas, southern Baja California, including Isla Guadalupe (Miller and Lea 1972). Intertidal and
to 40 m (min.: M. L. unpubl. data; max.: Eschmeyer and Herald 1983). D XXXIII-XXXVIII,! 1-13; A
11,31-35; Pect. 12-14; Pelvic 1,3; LLs 73-83; GR 5-8 + 12-13 = 18-20; Vert. 56-58.
Family Labrisomidae — Labrisomid Blennies
AUodinus holderi (Lauderbach 1907). Island Kelpfish. To 1 1.5 cm TL (M. L., unpubl. data). San Miguel
Island, southern California (D. Kushner, pers. comm, to M. L.) to Punta San Pablo (27° 12*N, 1 14°29W),
southern Baja California (Miller and Lea 1972). Intertidal and to 91 m (min.: M. L., unpubl. data; max.:
SCCWRP). D XXIV-XXVI,9-13; A 11,21-23; Pect. 13-14; Pelvic 1,3; LLs 47-54; GR4 + 9; Vert. 41-42.
Cryptotrema corallinum Gilbert, 1890. Deepwater Blermy. To 12.7 cm TL (Miller and Lea 1972). Off Cook
Point, San Miguel Island southern California (D. Schroeder, pers. comm, to M. L.) to Bahia San Quintin,
northern Baja California (Miller and Lea 1972). At depths of 24-195 m (min.: Miller and Lea 1972; max.:
M. L., unpubl. data). D XXVI-XXVIII,! 1-13; A 1-11,24-27; Pect. 13-15; Pelvic 1,3; LLs 65-75; GR 4-5
+ 8-12.
Labrisomus xanti Gill, 1860. Largemouth Blenny. To 17.8 cm TL (Thomson et al 2000). Agua Hedionda
Lagoon, La Jolla, and Santa Catalina Island southern California (C. Mack, B. Cantrell, and J. Nichols,
respectively, pers. comm, to M. L.); Isla Cedros and Isla Natividad (Ramirez- Valdez et al. 2015) and
(mainland) Bahia de Sebastian Vizcaino, southern Baja California into Gulf of California (Thomson et al.
2000) and to Bahia Chamela, Jalisco, Mexico (Galvan et al. 2016). Tide pools and to 1 1 m (min.:
Thomson and Lehner 1976; max.: LACM 31768.028. D XVII-XIX,10-13; A 11,17-19; Pect. 13-15; LLs
64-69; GR 3 + 6-7; Vert. 34.
Paraclinus mtegripinnis (Smith, 1880). Reef Finspot. To 7.8 cm TL (Rosales-Casian 1996). Santa Cruz Island
southern California (Rosenblatt and Parr 1969) and Naples, Santa Barbara County, southern California (S.
Norton, pers. comm, to M. L.) to Bahia Almejas, southern Baja California (Miller and Lea 1972).
Intertidal and to 15 m (Miller and Lea 1972). D XXVII-XXIII; A 11,18-21; Pect. 12-14; Pelvic 0-1,3;
LLs 34-39; GR 2 + 4 = 6; Vert. 37-39.
Family Chaenopsidae — Tube Blennies
Chaenopsis alepidota (Gilbert, 1890). Orangethroat Pikeblenny. To 15.2 cm TL (Miller and Lea 1972). Point
Sur, central California (T. Laidig, pers. comm, to M. L.) to Gulf of California (Thomson et al 2000). The
only known mainland population in southern California is in King Harbor, southern California (Stephens
et al 1989). At depths of 1-23 m (min.: Robertson and Allen 2002; max.: Allen and Robertson 1994). D
XVIII-XXI32-38; A 11,34-38; Pect. 12-14; Pelvic 1,3; GRt 1 1-12; Vert. 56-60.
194
SOUTHERN CALIFORNIA ACADEMY OF SCIENCES
Table 1 . Continued.
Neoclinus blanchardi Girard, 1858. Sarcastic Fringehead. To 30.5 cm TL (Miller and Lea 1972). Bodega Bay,
northern California (D. Stephens, pers. comm, to M. L.) to Isla Cedros, central Baja California (Miller and
Lea 1972). At depths of 3-73 m (min.: Miller and Lea 1972; max.: Carlisle 1969). D
XXIII-XXVII,15-18; A 11,26-30; Pect. 14-15; Pelvic 1,3; LLs 20-27; GR 4-6 + 8 = 12-14; Vert. 46-49.
Neoclinus stephensae Hubbs, 1953. Yellowfin Fringehead. To 10 cm TL (Miller and Lea 1972). San Francisco,
northern California (Ryan 1986) to Punta San Hipolito, central Baja California (Miller and Lea 1972).
Intertidal (Hubbs 1953) to 27 m (Miller and Lea 1972). D XIV-XXVII,15-18; A 11,29-31; Pect. 15; Pelvic
1,3; LLs 19-20; GR 6-8 + 12-14 = 18-22; Vert. 47-50.
Neoclinus uninotatus Hubbs, 1953. Onespot Fringehead. To 25 cm TL (Eschmeyer and Herald 1983). Bodega
Bay, northern California to northern Baja California (Eschmeyer and Herald 1983). Surf zone to 55 m
(min.: Carlisle et al. 1960; max.: Fay et al. 1978). D XXIII-XXVII,14-17; A 11,26-31; Pect. 14-16; LLs
17-26; GR 3-5 + 8-11 = 1 1-16; Vert. 47^9.
Through all of these sightings we were fairly confident in our identification of this species as
L. xanti, based on overall appearance and coloration of the breeding males. However, we felt
that publishing this report had to await our being able to examine a specimen. This opportunity
was provided by the third author (BC) who caught three individuals, using hook-and-line, on 30
June 2016 in Agua Hedionda Lagoon (33°08.8’N, 1 17°19.9’W). He caught these specimens in
an area of the lagoon that is lined by small boulders that occur from above the tide line into the
shallow subtidal. He reports that of the first three fish he caught one was a male and two were
females. Returning on 6 July 2016, he caught five more at low tide. Good water clarity allowed
him to see other L. xanti under a number of barely subtidal boulders.
These five specimens were deposited in the Scripps Institution of Oceanography Marine
Vertebrate Collection (SIO 16-30) and range in size from 97.2 to 122.3 mm SL. All specimens
fit the description of L. xanti (Hubbs, 1953), having relatively few cephalic sensory pores
(compared to the similar species L multiporosus), no teeth on the palatine, XVIII-XIX dorsal-
fin spines, 12-13 dorsal-fin rays, two anal-fin spines and 16-18 rays. The largest specimen is
a ripe male that was bright red with iridescent blue spots when captured. Three specimens are
females with ripe eggs, confirming the presence of spawning-capable individuals in southern
California waters.
Prior to this the known distribution of the Largemouth Blenny included the Pacific coast
of Mexico, from the outer Baja peninsula, the Gulf of California, and southward to southern
Mexico (Hubbs 1953; Springer 1959; Thomson et al. 2000). It is known from throughout
the Gulf of California from Roca Consag (SIO 04-124; 31°7.3'N, 114°29.0'W) southward to
Mazatlan and is the most common species in the genus found in the Gulf (Thomson et al.
2000). It is found along the Pacific coast of southern Mexico with confirmed records as far
south as Bahia Chamela, Jalisco (Galvan- Villa et al. 2016). It has also been recorded from the
Islas Tres Marias (Erisman et al. 2015) including Isla San Juanito (SIO 62-8, 62-9; 21°43.5’N,
106°42.3’W) and Isla Cleopha (SIO 62-56; 2ri5.5'N, 106H7.6'W), as well as Isla Clarion
(LACM 32097-47; 18°2TN, 114°43'W). Reports of the species from Peru (e.g.. Love et al.
2005) and Ecuador (Bearez 1996) appear to be based on its inclusion in keys to fish species
of that region (Chirichigno 1974; Chirichigno and Velez 1998). It was listed as occurring in
northern Chile in 1999 (Sielfeld et al. 2010) but that record may be based on the similar species
L multiporosus, known to occur in that area (Hubbs 1953; Springer 1959). Labrisomus xanti
was not recorded in a detailed systematic treatment of related blennies from the Pacific coast of
South America (Stephens and Springer 1974), and to our knowledge no specimens from south
of Mexico exist. Thus its occurrence south of Mexico is unconfirmed.
LABRISOMUS XANTI, NEW TO CALIFORNIA
195
Along the outer coast of Baja California L xanti had been recorded as far north as Puerto Mala
Arrimo in Bahia San Sebastian Vizcaino (SIO 14-174, formerly W51-224; 27°48'N, 1 14°43'W).
Hubbs (1953) reported the species (as Labrisomus xanthusi) from Isla San Benito based on two
specimens collected in 1950 (SU 17545; ca 28°18*N, 115°35*W). The species has also been
reported from Rocas Alijos (ca 24°57.5’N, 115°45’W) based on visual observations (Gotshall
1996). The southern California records represent the northernmost occurrence of the species,
extending its known range approximately 626 km northward from Isla San Benito to Santa
Catalina Island, California.
These records are the first from California. Whether the species arrived in these waters as
larvae, juveniles, or as adults (unlikely given their benthic habits), is unknown. We note that
the first individuals observed were adults. It is one of the numerous tropical fishes that arrived
in California waters during the strong El Nino of 2015. While we have documented that the
fish were breeding off La Jolla in 2015 and Agua Hedionda in 2016 it remains to be seen
whether recruitment from these spawning sites will be successful. We note that as of fall 2016,
no young or newly recruited individuals have been observed. Thus, it is possible that successful
reproduction will not occur and that this species will disappear over time from California waters.
Key to the California Kelp, Labrisomid, and Tube Blennies, Families Clinidae,
Labrisomidae, and Chaenopsidae
1 a Large ocellus present in posterior portion of dorsal fin (between 22”^ to 27^^ dorsal-fin
spines); dorsal fin wholly of spines ............ Paraclinus integripinnis (Labrisomidae)
lb No ocellus in dorsal fin as above; dorsal fin with both spines and soft-rays 2
2a Greatest body depth into total length more than 10 times; more soft-rays than spines in
dorsal fin Chaenopsis alepidota (Chaenopsidae)
2b Greatest body depth into total length less than 8 times; more spines than soft-rays in
dorsal fin 3
3a Maxillary extending well behind eye .4
3b Maxillary not extending behind eye .......................... ............ .6
4a Supraorbital cirri divided from base; no large ocellus in center of membrane between
and 2"^ dorsal spines; total gill rakers 18-22; head length 4.2-5. 3 into standard
length NeocUnus stephensae (Chaenopsidae)
4b Supraorbital cirri simple or divided only on distal half; ocellus present between 1 and
2nd (jorsal-fin spines; total gill rakers 1 1-16; head length 3. 5-3. 8 into standard length. . . 5
5a One ocellus in dorsal fin between and 2"^ spines, none between 5* to
9* spines; anteriormost supraorbital cirrus longer than eye and divided at tip
.NeocUnus uninotatus (Chaenopsidae)
5b Two ocelli in dorsal fin (rarely one; if one, located between P^ and 2"^ dorsal spines),
one between P^ and 2"^ spines, the other between 5* to 9* spines; all supraorbital cirri
shorter than eye and undivided NeocUnus blanchardi (Chaenopsidae)
6a From 3b: maxillary not extending behind eye
Tail forked; head elongated and pointed; anal-fin soft-rays 30 or more
................................................. .Heterostichus rostratus (Clinidae)
6b Tail rounded (in adults); head not as above, more stout; anal-fin soft-rays less than 30. . . 7
7a Pectoral fin long, extending beyond P^ anal-fin soft-ray; maxillary goes into head less
than 2.5 times 8
1 96 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES
7b Pectoral fin short, not extending to 1 anal-fin soft-ray; maxillary goes into head more
than 2.5 times 10
8a Ocellus between 2^^ and 3^^ dorsal-fin spines typically present; supraorbital cirri heavily
branched; anal-fin soft-rays 17 to 19 Labrisomus xanti (Labrisomidae)
8b No ocellus on dorsal fin (Island Kelpfish may have dark patch on and 2^^^ dorsal
spine); supraorbital cirri simple, with 2 or more tips; anal-fin soft-rays 21 or more ..... 9
9a Lateral line descends to midbody immediately posterior to tip of pectoral fin; anal-fin
soft-rays 21-23 ......................... Alloclinus holderi (Labrisomidae)
9b Lateral line remains in upper portion of body for at least 2/3 of distance to caudal fin;
anal-fin soft-rays 24-27 ............. ..... Cryptotrema corallinum (Labrisomidae)
10a Dorsal-fin soft-rays equally spaced, 7-10 in number; total length may be >16 cm
Gibbonsia metzi (Clinidae)
1 Ob Dorsal-fin soft-rays not equally spaced, posterior spacing wider than anterior, 5-8 in
number; total length < 1 6 cm ..11
1 la Scales present on caudal fin; ocellus on body with ring Gibbonsia elegans (Clinidae)
1 lb No scales on caudal fin; ocellus on body with no ring
Gibbonsia montereyensis (Clinidae)
Acknowledgments
We thank Callie Mack, Tara Howell, and Roger Uzun for bringing this species to our attention
and to John Moore, Wendy Dorr, Bill Bushing, Janna Nichols, Dan Richards, and Mark Steele
for further observations. We thank John Snow for helping us obtain the specimens, and Rick
Feeney for confirming identifications of museum specimens. The following researchers reviewed
the key: Don Buth, Craig Campbell, Dario Diehl, Rick Feeney, Robin Gartman, Peter Major,
Jim Mann, Mike Mengel, Terra Petry, Bill Power, Jim Rounds, and Fred Stern.
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Bull. Southern California Acad. Sci.
115(3), 2016, pp. 198-200
© Southern California Academy of Sciences, 2016
Records of Wahoo, Acanthocyhium solandri (Scombridae) ^
from California
Richard F. Feeney and Robert N. Lea
Natural History Museum of Los Angeles County, Section of Ichthyology, 900 Exposition
Boulevard, Los Angeles, California, 90007, rfeeney@nhm.org
The summers of 2014 and 2015 generated many tales of warm-water fishes being caught
in the local southern California sport fishery, including Dolphinfish (Coryphaena hippurus).
Blue Marlin {Makaira nigricans), Shortbill Spearfish {Tetrapturus angustirostris), Yellowfin
Tuna {Thunnus albacares), and Wahoo {Acanthocyhium solandri) among other tropical species.
The news media (both print and television), sport fishing reports, and photographic records
of Wahoo caught off California were numerous. For example, Phil Friedman (PFORadio.com)
reported Wahoo being caught at 14-Mile Bank, off Orange County (33°23.92'N, 1 18°00.20'W)
on October 4, 2015. Alex Dobuzinskis (Reuters, November 13, 2015) reported that in 2015 there
were 256 catches of Wahoo by party boats from Southern California according to Chad Woods of
the Sportfishingreport.com. Currently, Kells, Rocha, and Allen (2016) list the range as “recently
recorded from Newport Beach and San Diego, CA. Historically south of the U.S. -Mexican
border to Peru, including southern Gulf of California and Galapagos Islands.”
There have been unsubstantiated reports from previous years. Pete Thomas writes of a Wahoo
being snagged in Alamitos Bay in 201 0^ but, it may have been transported there by long-
range fishing vessel and released. In the period of 1997-99 while compiling records of tropical
fishes occurring off California during the 1997-1998 El Nino event. Lea and Rosenblatt (2000)
received several reports of Wahoo being caught off southern California. However, without
photo documentation or a substantiating specimen, these reports were not included. A search
of all the museum online databases revealed no preserved museum specimens from north of
the United States - Mexico boundary. There is one LACM specimen (37950-1) from the San
Pedro Fish Market, California, recorded in 1966 (a year of normal sea surface temperature) but
with no specific locality data. This specimen could have reached the market from anywhere
in the eastern tropical Pacific. To date, there have been no museum specimens preserved from
California waters, this being the first.
The first Wahoo documented from California was caught on August 30, 2014 and weighed in
at the Balboa Angling Club in Newport Beach (Western Outdoor News, Sept. 5, 2014). The fish
was caught by Eric Kim about 32 km (20 mi.) off Newport near the 267 spot (approx. 33°18'N,
1 17°50'W). It measured 152.4 cm (60 in.) in length and weighed 22.7 kg (50.1 lbs.). Following
this catch there were at least eight additional Wahoo landed in September. These came from
three areas: off San Diego (9 Mile Bank and Hidden Bank), San Clemente Island, and the waters
outside Dana Point. Weights for these fish were from 15.9 to 21.5 kg (35 to 47.3 lbs.). In late
October, a 38.2 kg (84.3 lbs.) fish was caught out of Dana Point Harbor; the water was 22.7° C
(72.8° F)^. In October there were several reports of Wahoo, in the 18-22 kg (40-48 lbs.) range
that were landed by spear fishermen^.
'http://www.petethomasoutdoors.eom/2010/09/believe-it-or-not-angler-catches-a-wahoo-in-alamitos-bay.html
^http://www.sportfishingmag.com/news/angler-lands-biggest-wahoo-ever-southern-california“Waters
^https://www.youtube.com/watch?v=BUgnwL4r2sI
198
CALIFORNIA RECORDS OF WAHOO
199
Fig. 1 . Acanthocybium soiandri collected near Oceanside, California, 2015 (LACM 58300-1 , head)
In 2015 the first Wahoo from California was caught on 29 August 2015 and weighed in at
the Balboa Angling Club (Western Outdoor News, Sept. 4, 2015). The fish was reported as
being caught by Mikko Monte at the 17-Fathom Spot (17°43.70'N, 1 19°09.60'W) and measured
151.7 cm (59.75 in.) and weighed 23.8 kg (52.58 lbs.). In October, a Wahoo was caught in
Santa Monica Bay, off Redondo Beach, which would establish that latitude as the most northern
record to date (Western Outdoor News, October 23, 2015). In mid-December 2015, a Wahoo
was caught on hook and line by Shawn Aulby near Oceanside, off Box Canyon (33°10.986'N,
1 17°26.26FW) in 91 m (300 ft.) of water. The head and tail were brought to the Natural History
Museum by Phil Friedman where they were photographed and cataloged as the first California
museum specimen, (LACM 58300-1, Fig. 1). Tissue was taken (T-001257) and stored in the
Ichthyology ultracold freezer.
Of the family Scombridae, Wahoo is perhaps one of the most distinctive members of this
group, exhibiting a number of unique characters (Collette and Nauen 1983). This species is
an elongate scombrid and the posterior end of the maxilla is concealed under the pre-orbital
bone. It has a relatively long snout, the snout being about as long as the rest of the head. In this
specimen, the snout (139 mm) is slightly shorter that the rest of the head (143 mm) or 49.3% of
head length. All of the other scombrid genera known to occur off California have snout lengths
Table 1. Head measurements and ratios of selected scombrid taxa known from California. (FL = fork
length, HL — head length, SL ~ snout length, HD — head depth at middle of eye. T. albacares is assumed to
be representative of the other species within the genus. Fitch and Craig are measurements from Fitch and Craig
(1964).
Taxon
Catalog
FL
HL
HL/FL
SL
SL/HL
HD
HD/SL
Acanthocybiuim soiandri
58300-1
282
139
0.49
100
0.72
Allothunnus failai
Fitch & Craig
722
187
25.90
55
0.29
Auxis rochei
6707-1
376
93
24.73
21
0.23
40
1.90
Auxis (hazard
6711-8
378
103
27.25
21.5
0.21
42
1.95
Euthynnus affinis
6711-12
200
58.5
29.25
16
0.27
27
1.69
Euthynnus lineatus
52024-14
385
115
29.87
30
0.26
62
2.07
Katsuwonus pelamis
48925-1
488
138
28.28
40
0.29
60
1.50
Sarda chiliensis
32031-1
410
109
26.59
37
0.34
47
1.27
Scomber japonicus
44756-4
209
55.5
26.56
18.5
0.33
23.5
1.27
Scomberomorus concolor
22582
550
114
20.73
37
0.32
45
1.22
S. sierra
32085-27
451
98
21.73
36
0.37
42.5
1.18
Thunnus albacares
48300-1
495
147
29.70
43
0.29
82
1.91
200
SOUTHERN CALIFORNIA ACADEMY OF SCIENCES
about 21-37% of head length (Table 1). Additionally, the ratio of the head height at the middle
of the pupil to the snout length (100/139 = 0.72) is low compared to other California scombrids
(1.18-2.07) (Table 1).
According to NOAA the El Nino conditions off California have persisted throughout 2015,
even into 2016, bringing anomalously warm water to northern latitudes (NOAA, Climate Pre-
diction Center/NCEP, 2016^). The addition of Wahoo to the California ichthyofauna brings the
number of species of scombrid fishes to 15. The Wahoo has a designation of “Least Concern”
on the lUCN Red List of Threatened Species (Collette et al. 2011).
Acknowledgements
We thank Shawn Aulby and Phil Friedman for catching and bringing in a specimen for us. We
thank Bruce Collette for providing comments on the manuscript. We also thank Camm Swift
for information on several catches.
Literature Cited
Collette, B.B. and C.E. Nauen. 1983. FAO Species Catalogue. Vol. 2. Scombrids of the world. An annotated
and illustrated catalogue of tunas, mackerels, bonitos and related species known to date. FAO Fisheries
Synopsis No. 1 25, 2: 1 37 p.
Collette, B., Acero, A., Amorim, A.F., Boustany, A., Canales Ramirez, C., Cardenas, G., Carpenter, K.E.,
de Oliveira Leite Jr., N., Di Natale, A., Die, D., Fox, W., Fredou, F.L., Graves, J., Guzman-Mora,
A., Viera Hazin, F.H., Hinton, M., Juan Jorda, M., Kada, O., Minte Vera, C., Miyabe, N., Montano
Cruz, R., Nelson, R., Oxenford, H., Restrepo, V., Salas, E., Schaefer, K., Schratwieser, J., Serra, R.,
Sun, C., Teixeira Lessa, R.P., Pires Ferreira Travassos, P.E., Uozumi, Y. & Yanez, E. 2011. Acanihocy-
bium solandri. The lUCN Red List of Threatened Species 2011: e.T170331A6750961. Available from:
http://dx.doi.org/10.2305/IUCN.UK.201 l-2.RLTS.T170331A6750961.en, checked on April 22, 2016.
Fitch, J.E. and W.L. Craig. 1964. First records for the Bigeye Thresher {Alopias superciliosus) and Slender Tuna
{Allothunnus fallai) from California, with notes on eastern Pacific scombrid otoliths. Calif Fish & Game
59:195-206.'
Lea, R.N. and R.H. Rosenblatt. 2000. Observations on fishes associated with the 1997-98 El Nino off California.
CalCOFI Rpt. 41:1 17-129.
Kells, V., L.A. Rocha, and L.G. Allen. 2016. A field guide to coastal fishes from Alaska to California. Johns
Hopkins University Press, Baltimore. 366 p
http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/lanina/enso_evolution-status-fcsts-web.pdf
CONTENTS
SMITHSONIAN LIBRARIES
9088 01925 3079
Site Fidelity of a Coastal Cactus Wren (Camphylorynchus brunneicapillus) on the
Palos Verdes Peninsula. Ann 141
Rodent Removal of Fallen Joshua Tree {Yucca brevifoUa) Fruits. Mark Borchert.„.=. 146
Status of the Endangered Chorro Creek Bog Thistle Cirsium fontinale var. obispoense
(Asteraceae) in Coastal Central California. Christopher P. Kofron and Neil
Havlik ... 1 5 6
Environmental Factors Influencing Reproduction in a Temperate Marine Reef Goby,
Rhinogobiops nicholsu, and Associated Behaviors. Michael T Schram and
Mark A. Steele 176
The Largemouth Belnny, Labrisomus xanti. New to the California Marine Fauna with
a List of and Key to the Species of Labrisomidae, Clinidae, and Chaenopsidae
found in California Waters. Milton S. Love, Julianne Kalman Passarelli, Ben
Cantrell, and Philip A. Hastings 191
Records of Wahoo, Acanthocybium solandri (Scombridae), from California. Richard
R Feeney and Robert N. Lea 198
Cover: Adult male Coastal Cactus Wren (Camphylorynchus brunneicapillus). Photograph courtesy of
Mai Lee.
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